1. In minimally invasive spine surgery (MISS)
Using an endoscope
In minimally invasive spine surgery (MISS)
Presenter’s name (Arial 20 pt)
Authors: AOSpine MISS Taskforce
Presenter’s title (Arial 20 pt)
Version: July 1, 2019

2. Learning objectives
Describe characteristics and set-up of working channel endoscopes
Identify differences between microscopes and endoscopes
Describe how to handle an endoscope
Explain key differences of working channel endoscopes for transforaminal vs interlaminar approaches

3. Definition of “endoscopy”
Use of a thin, tubular and coaxial surgical instrument that contains image transmission, illumination, and irrigation and a working channel
Two Greek roots:
ἔνδον (éndon) = inside
σκοπεῖν (skopein) = to observe

4. History of endoscopy Philipp Bozzini (Germany, 1805)
A candle-illuminated device to observe the living human body directly through a tube (Lichtleiter) to examine the urinary tract, rectum, and pharynx
Desormeaux (France, 1853)
Masaki Watanabe (Japan, 1950)
Developed early arthroscopes during the 1950 with a superior handmade lens
Philipp Bozzini
Antoin Jean Desormeaux
Masaki Watanbe

5. History of spinal endoscopy
Lumbar spine—common pathology—disc herniation: (“blind” procedures)
APLD (automated percutaneous lumbar discectomy)
Laser decompression (Mayer & Brock): “PELD” (percutaneous endoscopic laser discectomy)
Knight (2001) “Foraminoplasty”
Kambin & Zhou: “Kambin’s triangle” (safe working zone)
Kombin’s Triangle

6. Working channel endoscope
The endoscope has four components:
Optical system (typically a rod-lens system)
Illumination (Xenon light)
Irrigation channel
Working channel

7. Microscope vs working channel endoscope
Working distance
300 mm
3 mm
Illumination
300 mm from target
3 mm from target
Field of view
Restricted by the tubular retractor
Wide-angle panoramic viewing field
Line of sight
straight
15–30 degrees off axis
Image
3-D
2-D
Instruments
Standard bayonetted
Specialized tools
Retractor
Bladed, tubular
Tubular, irrigation fluid
Working corridor
Bimanual
Single working channel

8. Endoscope vs MISS ipsilateral recess decompression
Microscope
Endoscope
The endoscope allows for decompression and direct visualization of the ipsilateral traversing nerve root due to:
- Panoramic visualization
Off-angle (15°) visualization
Narrow tubular retractor (endoscope: diameter 7–10 mm vs 18 mm MIS)

9. Endoscope vs MISS contralateral recess decompression
Microscope
Endoscope
The endoscope facilitates undercutting of the contralateral recess:
- Retraction of the thecal sac by continuous irrigation
- Protected side-biting burrs
- Illumination and camera within the spinal canal

10. Tubular retractor
Specialized tubular retractors exist for interlaminar and transforaminal applications.
The tubular retractor serves the following functions:
Protects operative field from tissue creep
Bevel functions as elevator
Bevel can be used to retract neural structures

11. Tubular retractor
Optimization of off-axis reach A–B: Retracting the tubular retractor brings the shaft of the endoscope into contact with the bony edge and allows the blunt dissector to be closer to the lateral wall (blue arrow) C – D: Given the eccentric working channel, turning the endoscope 180° and facing the bony edge brings the working channel into close proximity to the bony edge

12. Interlaminar viewing angle: 15°
Transforaminal
Interlaminar viewing angle: 15°

13. Transforaminal endoscope
General characteristics:
200 mm length approximately 4 mm working channel diameter approximately 4 mm
Viewing angle 30°
Selected indications:
Disc herniations
Foraminal stenosis
Lateral recess stenosis
3.7

14. How to handle the transforaminal endoscope
Hold endoscope with pistol grip
Control tubular retractor with index finger

15. Interlaminar endoscope
General characteristics:
Approximately 200 mm length
Approximately 4.5 mm working channel diameter
Viewing angle 15°
Selected indications:
Lumbar disc herniations (L4/5 and L5/S1)
Lateral recess stenosis
Spinal stenosis
Facet joint cysts
Contralateral foraminotomy

16. Central stenosis endoscope
General characteristics:
Approximately 160 mm length
Approximately 6 mm working channel diameter
Viewing angle 15°
Selected indications:
Lateral recess stenosis
Spinal stenosis
Face joint cysts

17. How to handle the interlaminar endoscope
Rest endoscope in the C between thumb and index finger
Control tubular retractor with index finger

18. Challenges and how to avoid and address
Topic
Common challenge or problem
How this can be addressed/avoided
1. Holding the endoscope incorrectly
Non-ergonomic position
Position it correctly in the hand from beginning and keep doing it
2. Understand and troubleshoot the parts of the endoscope
Eg, irrigation, light, and camera problems
Disassemble the parts—be able to assemble them all
3. Handling the working sleeve (tubular retractor)
Retractor in wrong position—bad rotation and depth or endoscope
Correct management of rotation and depth
4. No picture visible or field full of blood
“I don’t see anything”
Maneuvers and hemostasis management—train on simple models with water, etc
5. How to optimize the endoscope
Do not just use it like a microscope (when you do not realize what it can do)
Realize the full potential (use the depth to move almost anywhere)