Il Linfonodo Sentinella in Chirurgia: Attualità e Prospettive
Direttore: Prof. A. Liboni
20 gennaio 2012
Ferrara, ITALY
Il monitoraggio nervoso intraoperatorio
Gianlorenzo Dionigi, MD, FACS
Department of Surgical Sciences
UNIVERSITY OF INSUBRIA (COMO – VARESE) - ITALY
This report does not endorse any specific
Company or set of monitoring equipment
Exposure of RLN reduce the rate of RLN injury
No identification Localized
RLN
RLN
Lahey FH, Ann Surg 1938
1.6
0.3
Riddell VH, Lancet 1956
3.5
2.1
Jazko, Surgery 1994
7.9%
1.2%
Wagner, Br J Surg 1994
21%
6.9%
Hermann, Ann Surg, 2002
2.1%
0.9%
Dralle H, Surgery 2004
1.16%
0.63%
Chiang, Surgery 2005
5.1%
0.9%
Partially exposed
RLN
0.3%
-
Completely dissected
RLN
0.1%
-
Gold standards for RLN management
1.
Extensive knowledge of RLN anatomy
2.
Visual identification of RLN
3.
Exposure of RLN
4.
Experience & training
5.
Pre- & post-op. laryngoscopy
Why neuromonitoring?
RLN and laryngeal anatomy are the basis of
modern thyroid surgery
Why do we need more
than anatomical nerve identification?
Neuromonitoring: history
•Laryngeal palpation with stimulation of RLN: feel for laryngeal twitch
•Riddell published in 1970, studies over 1946-1960
•Palpation of posterior crico-arytenoid muscle, with stimulation of 0.5-2.0mA
•Galivan 1986
Evolution of RLN Monitoring
• Intra-operative invasive techniques
• Non-invasive surface electrodes
Lamadé W
Transtracheal monitoring of the recurrent laryngeal nerve. Prototype of a new tube
Intraoperative monitoring of the recurrent laryngeal nerve. A new method
Chirurg. 1996 & 1997
ETT
ETT electrodes
Stimulator
probe
NIM monitor
RLN identified both visually and electrically
Intraoperative evidence of RLN injury
Evidence RLN injury
Author
Reference
N
%
Bergenfelz A
Langenbecks Arch Surg 2008
1/10
11.3%
Chiang FY
Surgery 2005
3/40
7.5%
Lo CY
Arch Surg 2000
5/33
15%
Patlow CA
Ann Surg 1986
1/10
10%
Caldarelli D
Otolaryngol Clin North Am 1980
1/10
10%
Scandinavian Quality Register Thyroid Surgery
Intraoperative RLN injury causes
•
•
•
•
Section (mistake in surgical technique)
Ligature (without transection)
Mistake in hemostasis and dissection maneuvers
Stretch/traction
– Excessive traction during the medial traction of the thyroid lobe
– Excessive aspiration near to the nerve (suction)
• Compression/contusion/pressure
• Thermal/electrical injury
– Diffusion by haemostatic devices
• Ischemia
– Ligation of the inferior pole vessels before identifying RLN
– Excessive dissection of the nerve with ischemia
Types of nerve injury
– neuropraxia: simple contusion of a nerve
• treated by simple observation
• return to normal function over weeks to months
– axonotmesis: more significant disruption followed by
degeneration
• healing takes a prolonged time
– neurotmesis: complete division of a nerve
• requires surgical repair
anatomical nerve lesions are only exceptional
reasons for postop VC palsy
Dralle H. WJS 2008
Bergenfelz A . Langenbecks Arch Surg 2008
Chiang FY . Surgery 2005
Lo CY . Arch Surg 2000
Patlow CA . Ann Surg 1986
Caldarelli D. Otolaryngol Clin North Am 1980
AUDIT
True incidence of RLN injury
• No routine post-operative laryngoscopy 0.3% RLNP
• Routine postoperative laryngeal exams 7% RLNP
1. Evidence from the Literature (?)
Transient RLN palsy
Parameter
Odds ratio
P value
Permanent RLN palsy
Odds ratio
P value
Graves’ disease
1.40
<0.43
1.95
<0.37
Recurrent goiter
4.06
<0.0001
89.96
<0.0001
Thyroiditis
0.04
<0.83
0.02
<0.92
Uninodular goiter*
1.27
<0.41
1.43
<0.51
IONM
0.58
<0.008
0.30
<0.004
Am J Surg 2002
2. Evidence from the Literature (?)
19
Dralle H, WJS 2008
Reasons for RLN protection with IONM
• Adds early and definite localization of RLN
– To prevent visual misidentification
– To avoid excessive traction
– To identify extralaryngeal branches, anatomical variation,
distored RLN, non-RLN
• Adds confirmation of RLN
• Adds dissection of RLN
Nerve Identification
2mA
Nerve Confirmation
1-0.5mA
Nerve Confirmation
0.5mA
Why neuromonitoring?
The answer is very simple:
based on anatomical nerve assessment alone
1. the frequency of postop VC dysfunction is
more common than expected
2. because anatomical nerve lesions are only
exceptional reasons for postop VC palsy
Which is the fundamental difference
between visual identification and
RLN monitoring?
RLN monitoring can change strategy
Strategy changes in bilateral goiter
36 LOS at first side
16 unchanged strategy
↓
9 (56%) unilateral palsy
3 (19%) bilateral palsy
20 changed strategy
↓
20 (100%) unilateral palsy
0 bilateral palsy
When LOS is real:
How to treat RLN injury intraoperatively?
Intraop steroids*
(n=143)
NAR
Vocal corde
palsy
temporary
permanent
Recovery
(days)
No intraop steroids
(n=152)
194
173
11
1
12
1
28.6 (10-36)
37.4 (14-61)**
MEDICO-LEGAL ISSUES
• Reduction of major injury to patient
– Bilateral RLN palsy
• Recorded nerve signal
• Early differentiation between RLN related and
unrelated voice changes
• New standard of care (?)
US thyroid surgery monitored
Chiang FY, 2011
IONM procedures in Asia
IONM PREVALENCE IN EUROPE
Danmark
77%
2007
Godballe C, ETA Meeting, Lisbona,
Poland
5%
2010
Barcinsky M, Polish Endocrine Surgeon
Germany
90%
2011
Dralle H, Harvard Meeting, Boston
France
#6200
2008
Carnaille B, IONM study group
France
#10000
2010
Spain
#613
Spain
#1956
2009
Jan-april
2011
Carnaille B, IONM study group
Manuel Poveda, Madrid 2010
Manuel Poveda, Madrid 2011
PREVALENCE IN ITALY
source Medtronic Italy
German Association of Endocrine Surgeons
Langenbecks Arch Surg 2011;396(5): 639-649
http://www.dgch.de
2.6.1. Darstellung des Nervus laryngeus recurrens
Funktionsstörungen des Nervus laryngeus recurrens sind mit Stimmstörungen, Schluckstörungen und
Beeinträchtigungen der Atmung verbunden. Bei bilateraler Rekurrensparese ist häufig eine Tracheotomie
erforderlich.
Das Risiko, den N. laryngeus recurrens zu verletzen, wird durch das Ausmaß der Resektion und die individuelle
Lagevariante des Nerven bestimmt. Die schonende, das heißt nicht-skelettierende,
nervendurchblutungserhaltende präparative Darstellung des N. laryngeus recurrens mindert das
Schädigungsrisiko und sollte grundsätzlich sowohl bei Primäreingriffen als auch bei Rezidiveingriffen durchgeführt
werden (6, 18). Der visualisierte anatomische Nervenverlauf sollte vor und nach Resektion dokumentiert werden.
Ausnahmsweise kann auf die Darstellung verzichtet werden, wenn sich die Resektionsebene in sicherem Abstand
ventral der lateralen Grenzlamelle zum Nervenverlauf befindet (46).
Die Nichtdarstellung des Nervus laryngeus recurrens soll begründend dokumentiert werden.
Das intraoperative Neuromonitoring ersetzt nicht den Goldstandard der visuellen Nervendarstellung, sondern ist
nur in Ergänzung zu dieser einsetzbar. Das Verfahren kann die Identität des Nervus laryngeus recurrens sicher
bestätigen und seine Funktionsfähigkeit bei ungestörtem Überleitungssignal sehr wahrscheinlich machen, wobei
zur Erfassung des gesamten Nervenverlaufes die Stimulation über den Nervus vagus vor und nach Resektion
erforderlich ist (10, 17, 28, 48, 50). Die sicherste Methode zur Differenzierung zwischen Artefakten und
Aktionspotenzialen ist die Ableitung von Elektromyogrammen. Eine signifikante Senkung des
Rekurrenspareserisikos durch Einsatz des Neuromonitoring ist bislang nur bei Rezidiveingriffen gesichert (9, 28).
Polish Journal of Surgery (transl).
Guideline Statement of the Polish Study Group for Nerve Monitoring of
the Polish Club of the Endocrine Surgeons
Members of the Study Group for Nerve Monitoring of the Polish Club of
Endocrine Surgery during the conference on 16th of April 2011 in Krakow
opine that centers of thyroid surgery in Poland should be equipped with
nerve integrity monitoring systems.
Following the analysis of the published
data and based on our own experience the need to introduce routine training
courses of standardized technique of electrophysiological monitoring of the
recurrent nerves and employment of this technique in selected thyroid
operations was recognized".
Neuromonitoring for residents in
surgical training
• Incorporating new technology
• Teaching aid
• Elucidate errors
• Less-experienced surgeons
– IONM decrease RLN paralysis (Dralle H, 2004)
LIMITATIONS OF IONM
1.
RLN palsy still occur
2.
need for standardized and well-trained use to avoid pitfalls
3.
knowledge of most-common pitfalls
4.
ability to use troubleshooting algorithms
5.
IONM does not replace clinical judgment
6.
relatively low positive predictive value
7.
cost-effectiveness is still not evaluated
8.
need for further research focused on neurophysiology of the RLNs
9.
IONM of the external branch of the superior laryngeal nerve
10. thyroidectomy in local anesthesia
Conclusions
Why should RLN be monitored in any bilateral case ?
• RLN monitoring improves
– Nerve ID (Randolph GW, 2002)
– Clarification of RLN anatomy (Delbridge 2002)
– Nerve dissection (Chan WF 2006)
– Reoperations with pre-existing RLN morbidity (Gorentzy P, 2008)
• Intraoperative assessment of RLN function (non postoperative)
– Intraoperative prediction of post-operative function (prognosis) (Timmermann W, 2004)
– Prevention of bilateral RLN injury: “one-stage thyroidectomy” (Randolph GW, 2002)
– Elucidate where and how the RLN was injured (intraoperative evidence) (Chan WF 2006)
– Early differentiation between RLN related and unrelated voice changes (Dralle H 2004)
IONM technology in thyroid surgery
(IONM: intraoperative neuromonitoring)
IMPLICATIONS
CLINICAL PRACTICE
RESEARCH
EDUCATION
MEDICO-LEGAL
Surgeons should not overstate benefits of
neuromonitoring to patients
Modern Surgery
• ERADICATION OF DISEASE
• SAFETY OF PROCEDURE
• DOCUMENTATION