Dr. Zahid Iqbal Mir, MBBS, MS (General Surgery), DNB (General Surgery) has done his bachelors and masters in General Surgery from the prestigious Govt Medical College Jammu and DNB in General Surgery from NBEMS New Delhi. He is a passionate surgeon, earlier practising at Government Medical College, Jammu as Registrar in Department of General Surgery. Nowadays working as Senior Resident in Department of General Surgery, Government Medical College & Hospital, Sector 32, Chandigarh and a rising name in field of surgery. He is an enthusiastic, enigmatic and dedicated teacher as well. He is not just a resolute learner, but also an awe inspiring guiding light for his juniors, which makes him the most loveable and respected senior.

1. MAGNETIC GUIDANCE IN SURGERY
Dr. Zahid Iqbal Mir
MBBS, MS, DNB

2. CONTENTS
• HISTORY & WHAT WE KNOW
• SLNB — CURRENT PRACTICE
— NOVEL APPROACH
MAGNETIC
• TRIALS & STUDIES
• AXILLARY MRI USING CE SPIO (SUPERPARAMAGNETIC)
• CHANGING PRACTICE – CLINICAL NEED
• MAGS , MAGNETIC SURGERY

3. GUIDANCE IN CANCER SURGERY – WHAT WE
KNOW?
• SENTINEL LYMPH NODE – FIRST DRAINING LYMPH NODE
 CORRECT DETECTION & ASSESSMENT
 DETERMINING STAGE
 PLANNING TREATMENT
Concept of SNL
1977

4. Blue dye
approach -
1993
Confirmation by
radioactive tracer -
1994
Radioactive
tracer(99m Tc) - 1993

5. SLNB - CURRENT PRACTICE
 Kim et al (2006) - early stage breast cancer.
• 68 studies and 8059 patients (mean identification rate - 96%)
• Out of 68 studies, 18 used blue dye alone, 16 used radioactive
tracer alone, and 34 studies used the combined technique.
• FNR - 0% to 29% (mean - 7.3%) {combined (7.0%), blue dye
alone (10.9%), radioactive tracer alone (8.8%)}
 Valsecchi et al. (2011) - melanoma
• 71 studies and 25,240 patients (mean identification rate -
98.1%)
• Radioactive tracer (in combination with lymphoscintigraphy)
and blue dye added in 89% of the studies.
• FNR - 0.0% to 34.0%, (mean - 12.5%)
Cancer. 2006;106:4-
16
J Clin Oncol.
2011;29:1479-87

6. Current standard of care for performing SLNB in
breast cancer and melanoma is the combined
technique of radioactive tracer and blue dye — High
mean identification rates in breast cancer and
melanoma — 96% and 98%, respectively.
Radiotracer use extended to:
 Radio guided occult lesion localization (ROLL) for the
management of non palpable breast cancers (1998)
 Sentinel node and occult lesion localization (SNOLL)
• Successful complete resection rate – 82% to 90.5% with an
SLNB success rate - 88.2% to 100%
• Reduced reoperation rates for involved surgical margins
• Reduced operating times compared to conventional wire
guided surgery
Breast. 1998;7:11-3 Breast. 2013;22:1034-40 Breast.
2013;22:383-8

7. NOVEL APPROACH FOR SLNB-
MAGNETIC
 Why the need for NOVEL technique ?
Drawbacks of
radioisotopes:
• Radiation exposure
• Legislation (Surgical
licensing, Waste
disposal)
• Poor image localisation
Drawbacks of blue dye:
• Obscuring surgical
field
• Tattooing of skin
• Rare allergic reaction
(Patent Blue V – 0.9%)
Magnetic technique for identifying the sentinel node(s) using
a superparamagnetic iron oxide (SPIO) magnetic tracer
injected subcutaneously into the breast and then detected
using a handheld magnetometer — Colour change (brown or
black) in the lymph nodes - localization using a handheld
probe.

8. SLNB with a subcutaneous injection of SPIO (Endorem, Guerbet, France) into
the breast: a Sentinel node identified in right axilla. b Sentinel lymph node with black
SPIO deposition. c MRI showing the injection site and a sentinel node. d 2 SNL and a
lymphatic tract, seen on axillary MRI

9. Hand held magnetometer (Sentimag,
Endomagnetics Ltd , UK)

10. Injectable magnetic tracer
(Sienna+, Endomagnetics
Ltd, UK)
 Sienna+, a blackish-
brown sterile, aqueous
suspension of super
paramagnetic carboxy-
dextran coated iron
oxide particles, is 60 nm
(Z-averaged diameter ;
<0.25 polydispersity),
ideally suited for SLNB
a. The magnetometer identified a node with a high count in the right
axilla b. The node is blue c. the same node is also black on the other side

12. TRIALS & STUDIES

13.  First to evaluate the magnetic technique for SLNB against
the standard technique in breast cancer (161 patients)
 The SLN identification rate = 95.0% (standard technique)
and 94.4% (magnetic technique)
 404 SLNs were removed and the node retrieval rate was
1.9 nodes per patient (standard) and 2.0 (magnetic
techniques).

14.  The Central European SentiMag Study in 150 patients, who
underwent SLNB, with the magnetic and radioisotope
technique only (no blue dye).
 This study reported an SLN identification of 97.3% for
radioisotope alone and 98.0% for the magnetic technique
 mean node retrieval of 1.8 for radioisotope alone and 1.9
for the magnetic technique

15. • Sentinel node identified with
black SPIO stained
• Black stained after H&E
evaluation
 120 patients with clinically node
negative early breast cancer without
blue dye.
 No drainage in 2 patients by either
technique
 They also concluded that detection of
SLNs using SPIO (98.3%) is not inferior
to the radio-tracer technique (95.7%)

16.  181 patients from nine Spanish hospitals
 For identification of SLN, patients were injected with radioisotope
and blue dye was optional. In addition the magnetic tracer was
injected
 20 minutes wait between injection of the magnetic tracer and
transcutaneous readings
 Piñero-Madrona et al. found an intraoperative identification rate of
97.2% (176/181) and 97.8% (177/181) with the magnetic and
combined techniques, respectively

17. 30 patients who underwent
the magnetic technique (using
a different device) with blue
dye, but no radioisotope
SLN identification rate of 77%,
80%, and 90% for the magnetic
technique, blue dye only, and
magnetic technique with blue
dye, respectively.

18. The magnetic technique consists of an
injectable SPIO magnetic tracer injected
subcutaneously into the breast and a
handheld magnetometer that is used
intraoperatively to identify SLNs
Clinical trials in breast cancer - a high SLN
identification rate (93.7-98.3%) using the
magnetic technique for SLNB but patients
also received radioisotope or radioisotope
and blue dye

19. FURTHER APPLICATION OF MAGNETIC
TECHNIQUE
 Nonpalpable lesions ( breast) - Surgical excision
using wire-guided localization (WGL) and axillary
staging using SLNB.
 WGL is limited by - poor patient satisfaction,
technical difficulties such as wire migration, poor
cosmetic outcome, high reoperation rates,
diathermy burns, and negative impacts upon
theatre scheduling due to necessity of radiology
input
Alternative- benefits over WGL , but their uptake –
limited due to dependence upon radioisotopes and
its associated legislative implication for handling &
disposal

20.  Single US guided intratumoral injection of 0.5 mL of magnetic tracer to localize
the nonpalpable lesion and perform concurrent SLNB
 Peak "hot spot" - excised.
 Concurrent SLNB was performed as per the standard magnetic technique used in
the SentiMAG Multicentre Trial
 Successful localization of all 20 nonpalpable breast cancers (out of 32, 12-
palpable) with re-excision for involved margins in 2 patients.
 SLN identification rate with the magnetic tracer - 85%; radioisotope and blue dye
97% ; magnetic technique and blue dye - 97%.

21. Magnetic sentinel node and occult
lesion localization procedure
Injection of 0⋅5 ml of
magnetic tracer (1) is followed
by placement of a non-
ferromagnetic marker coil (2),
solely for the purpose of
facilitating specimen
intraoperativeradiography –
not as part of the localization
procedure.
Intratumoral injection (0⋅5 ml
magnetic tracer) administered
under ultrasound guidance in
the radiology suite.

22. Ultrasound-guided skin
marking over the site of the
breast cancer
Intraoperative specimen X-
ray - cancer located in the
centre of the excised
specimen (arrows mark
radiological tumour extent). A
marker coil is visible near the
tumour centre. Standard
orientation clips are visible

23. MELMAG - Magnetic technique for SLNB against the standard
technique (radioisotope and Patent Blue Dye).
 Patients with primary cutaneous melanoma who were scheduled
for SLNB and clinically AJCC stage IB-IIC2
 In addition, an MRI subprotocol evaluated the accuracy of MRI for
the localization of SLNs.
 Out of total 133 patients 129 patients were available for analysis
(four excluded).
The SLN identification rate was 97.7% (Standard technique) ; 95.3%
(magnetic technique) ; 95.3% radioisotope alone

24.  Current breast lesion localization
using a wire has disadvantages such
as poor patient satisfaction and wire
migration
 The magnetic tracer can be injected
into the primary tumor, localized with
a handheld magnetometer and then
the tumor can be excised
 The magnetic technique for SLNB
evaluated for melanoma in the
MELAMAG trial demonstrating a high
SLN identification rate of 95.3%.

25. • 924 patients randomized to
undergo SLNB with the magnetic
technique or the standard
technique, including at least 194
patients with involved SLNs.
This non-inferiority trial assumed a
97% SLNB identification rate with both
techniques, and is largest trial of the
magnetic technique and a crucial trial
of a non-radioisotope technique for
SLNB.

26. MAGNETIC NANOPARTICLES -
SPIO ( SUPERPARAMAGNETIC IRON
OXIDE )

27. ROLE OF AXILLARY MRI USING CE - SPIO
 Axillary MRI - alternative to SLNB in determining axillary burden
 Data from studies using SPIO - sensitivity (98%) and specificity (96%) for the
detection of axillary involvement
 Meng et al. assessed the cost-effectiveness of MRI and PET for the evaluation
of axillary lymph nodes in early breast cancer — if MRI could accurately
diagnose axillary involvement, the most cost-effective strategy was to
replace SLNB with axillary MRI.
• True positive patients - single procedure ALND replacing two, SLNB followed
by ALND
• True negative patients - no surgery
Eur J Surg Oncol.
2011;40:S50

28. • Challenge - false positive MRI (6.3%) and SLNB (0.2%)
• Harnan et al - MRI (assessment of axillary lymph node status
in early breast cancer) ; mean sensitivity (90%) and specificity
(95%)
• Highest mean sensitivity and specificity was seen with SPIO-
enhanced MRI - 98% and 96%, respectively.
 This technique could potentially identify patients with
significant axillary involvement preoperatively, who therefore
require ALND and also lead to the concept of "selective
axillary surgery" of involved nodes, combining preoperative
imaging with novel techniques to guide surgeon
intraoperatively
Eur J Surg Oncol.
2011;37:928-36

29. CHANGING PRACTICE IN CANCER
SURGERY
• Alternative to radioisotope dependency and
increase uptake of "gold standard" procedure.
• Noninferior to the standard technique
• Does not depend on radioisotopes.
• Evaluated in melanoma and for lesion
localization and concurrent SLNB in breast
cancer.

30. CLINICAL NEED ?
• Magnetic technique - not evaluated on its own
(without blue dye or radioisotope) - ? RCT
 Need - academically run (independent) and
noncommercial RCT to establish if the
magnetic technique should be used routinely.
 Tight margin for noninferiority
 Changed practice across - colorectal, penile,
and anal cancers

31. Magnetic technique –
• Credible alternative to radioisotope
dependence in the performance of
lymphatic mapping across a range of
cancer
• Provides the opportunity for extended
applications including the use of MRI for
axillary staging, "selective axillary
surgery", and localization surgery for
clinically occult lesions.
Further assessment within randomized controlled clinical
trials is now necessary in order to bring these innovative
applications into clinical practice.

32. MAGS
 Two magnetic elements matched through the abdominal or thoracic wall.
 Internal magnet can be inserted through a small single incision and then
moved into position by manipulating the external component
video camera system
remotely controlled surgical tools
Reducing instruments fencing, a serious inconvenience of the uniportal
access.
• Latest prototypes - LED illumination and wireless antenna
• Originally - laparoscopic surgery, suit optimally the characteristics of the
chest wall and meet the specific demands of VATS — in terms of
ergonomics, visualization and surgical performance
• Less risks for the patients and an improved aesthetic outcome.

33. Wireless steerable endoscope (WSE) prototype is held
against gravity by a magnet under a wooden plank
mimicking attachment to the internal wall of a body cavity
(A) The WSE can (B) slide; (C) axially rotate; (D) multiple
viewing directions

34. Schematic representation of MAGS
platform
(a) Deployment trocar
(b) MAGS camera
(c) Retractors
(d) Robotic cauterizer
(e) External magnets.

35. • 10 patients underwent laparoscopic cholecystectomy with
the LevitaTM Magnetic Surgical System
• Mean age at the time of surgery - 49.0
• Average BMI - 27.6 kg/m2.
• Average operative time - 64.4 min.
• No perioperative complications.
• Surgeons reported that the magnetic grasper was easy to
use and provided adequate tissue retraction and exposure.

36. Retraction of the gallbladder
with the LevitaTM Magnetic
Surgical System
LevitaTM Magnetic Surgical
System, displaying the
deployable grasper (DG) and
the external magnet (EM)