History (Past)
The year was 1926, when Egaz Moniz, a Portuguese neurosurgeon, visualized blood vessels
in the brain with radiographic means using strontium and lithium bromide initially
and 25% sodium iodide solution later on, developing the first cerebral angiogram.[1] But long before that in year 1904, James Dawbarn, again a surgeon, injected beeswax
mixture into the branches of external carotid artery for head and neck malignancies
after surgically exposing them.[2] Surprisingly, therapeutic neurointerventional development took precedence over diagnostic
cerebral angiogram during the early days; long before Serbinenko,[3] Russian neurosurgeon introduced detachable balloons in 1971 for treatment of traumatic
carotid cavernous fistula (CCF) and saccular aneurysms. It was Brooks[4] in 1930 who described embolization of CCF by muscle pieces.
The year 1953 was the year that one may consider to be a watershed point in the history
of neurointervention (NI) when Dr. Sven Seldinger, a Swedish radiologist, developed
a percutaneous arterial puncture technique using a needle and wire.[5] The first use of catheters for cerebral angiography is credited to another Swedish
radiologist named Stig Radner,[6] who, way back in 1947 while trying to catheterize coronary vessels through radial
artery, accidently cannulated vertebral artery and performed cerebral angiography.
Both these innovations opened up numerous possibilities in the field of NI, but neurosurgeons
ignored these advances and hence most of the neurosurgeons world over continued to
perform diagnostic cerebral angiography via carotid artery with direct needle puncture
and radiologist catheter-based cerebral angiography via Seldinger technique.[7] Although over the next decade or so—till the invention of computed tomography (CT)
in 70s and subsequent diagnosis of brain lesion by CT when neurosurgeons all together
completely stopped doing even carotid punctures and radiologists promoted themselves
from film changers and readers to interventionists—little progress was made in the
field of arteriovenous malformation (AVM) apart from embolization by Luessenhop and
Spence[8] by exposing internal carotid artery and injecting methacrylate spheres, and Alskne
and Fingerhut,[9] who stereotactically inserted needle and directed iron particles into an aneurysm
via magnetic field. Meanwhile, radiologists gained experience with catheter-based
angiography, and Boulos et al[10] embolized brain AVMs from a catheter in the internal carotid artery. Similarly,
Newton and Adams[11] treated spinal cord malformations. Kerber and Pevsner[12] independently developed silicone microcatheter which was used in 1974 to embolize
occipital AVM. Although Serbinenko[3] had already published his study of detachable balloon for treatment of CCF and aneurysms
in 1971, by that time European radiologists already took the world stage in NI. Djindjian[13] was the most famous in those times as he imparted training to neurointerventionists
of France and other countries.
In 1991, Guido Guglielmi,[14] an Italian neurosurgeon, and Ivan Sepetka developed detachable platinum coil for
the endovascular treatment of aneurysm, changing the course of vascular neurosurgery
for years to come; however, again, neurosurgeons across the world remain skeptical
regarding this novel treatment modality even when ISAT[15] was started in 1994 and published in 2002. It was not that the coils were not used
before but the unique concept involved redesigning and controlled detachment of coils
unlike the pusher and free coils developed by Hilal.[16] Also, what was missed in all these years of hardware development was a contribution
by an engineer named Engelson in 1985 at Target Therapeutics who invented a variable
stiffness microcatheter with radiopaque marker at the tip along with a steerable microguide
wire.[17] In subsequent years, endovascular aneurysm treatment technique and technology advanced
at a rapid pace from different modifications of coil for better packing density of
aneurysm to balloon remodelling technique[18] and stent-assisted coiling for wide neck and broad-based aneurysms. Most of the
aneurysms considered uncoilable before are now being treated with latest devices like
flow diverter device[19] and intrasaccular devices.
The year 2015 was the most impactful year in the history of the neuroendovascular
field as numerous trails[20]
[21]
[22] confirmed the benefit of mechanical thrombectomy over intravenous actilyse alone
among patients afflicted with acute ischemic stroke with large vessel occlusion. Again,
as in previous years, basking in the glory of newer successful modality, more techniques
and hardware, right from thromboaspiration catheters and newer stent retrievers to
balloon-guide catheters, were being developed to make this form of treatment more
successful. In 2018, with DAWN[23] and DIFUSE 3[24] trials, a treatment window for mechanical thrombectomy was extended from 6 hours
to 24 hours in a selected group of patients. Although Guglielmi was known for his
contribution of coils in aneurysm treatment, one of his lesser known, but arguably
his biggest contribution was intra-arterial therapy in acute ischemic patients way
back in 1991.
In India, neuroradiologists played the primary role of neurointerventionist in most
public institutes, except a few. The G.B. Pant Institute, Delhi, is one where neurointervention
is part of the training of neurosurgical resident by virtue of the vision of Prof.
A. K. Singh. Prof. Daljit Singh is currently training the next generation of neurointerventionists
among neurosurgeons (the subsequent history of NI in India is through personal communication
with Dr. Anil Karapurkar).
All departments of neurosurgery did their own diagnostic neuroradiology until the
advent of CT scan which became available in 1978 at AIIMS and at Mumbai in 1982.
Diagnostic neuroradiology included plain radiography, ventriculography, cerebral angiography,
myelography, and PEG (pneumoencephalography). Cerebral angiography was carried out
by the percutaneous puncture of the carotid artery in the neck.
At KEM Hospital and Seth G S Medical College, Mumbai, transfemoral cerebral angiography
was started in early 1976. NI was started in a small way in 1977. Dr. Sunil Pandya,
Professor and HOD neurosurgery, performed the first procedures. Subsequently, Dr.
R. D. Nagpal and Dr. Anil Karapurkar also started conducting NI procedures. After
there was a serious complication, it was decided to go for formal training in NI.
Karapurkar was deputed by the Bombay Municipal Corporation for undergoing training
in France. He was also provided financial support by the R D Birla Smarak Kosh of
Bombay Hospital. His training tenure in France lasted from September 1980 to March
1981. In this period, 2 months were spent at The Hospital Foch in Suresnes for trans-sphenoid
surgery under Prof. Gerard Guiot, 2 months under Prof. Bernard Pertuiset at the Pitie
Group of Hospitals, Paris, for microvascular surgery, and under Prof. Luc Picard at
the University Hospital, Nancy, France for NI (interventional radiology [INR]). Prof.
Luc Picard had been trained by Prof. Rene Djindjian. They were the pioneers and doyens
of neurovascular intervention worldwide.
Immediately thereafter, Karapurkar also spent 3 weeks as an observer at the University
Hospital London, Ontario, under Prof. Gerard Debrun in April 1981. Here he observed
a complication, the management of which served him well throughout his career. The
complication was a microcatheter stuck in a distal branch of the posterior cerebral
artery. It was managed by performing an angiogram from the other femoral artery to
confirm robust circulation. The catheter was then cut in the groin and left behind.
In 1987, under the Indo-French Exchange Program (FIAP), Karapurkar underwent further
training under Prof. Picard at Nancy and Prof. J M Moret of Fondation Ophthalmique
de Rothchilde, France. In 1985, he conducted live workshops with operations and didactic
lectures for neuroscientists and radiologists from across India. Live operations were
telecast from the cath laboratory to the auditorium for the first time with two-way
live communications. Dr. N. K. Mishra, Professor of neuroradiology at AIIMS, had attended
this first of its kind of workshop in India. Prof. R. V. Phadke, who later became
HOD neuroradiology at SGPGI Lucknow, had his first exposure to NI. Prof. Luc Picard
of Nancy, France, was the guest faculty. In 1991, he underwent a 1-month observership
under Prof. J. M. Moret of Rothschilde Ophthalmic Hospital, Paris, (Fondation Ophthalmique
de Rothchilde). From 1989 to 1994, Dr. Ravi Ramakantan, Head of the radiology department,
would sometimes assist in brain AVM procedures. Until 1993, only neurosurgery residents
were being trained in NI. From 1993, the department of radiology deputed a resident
for exposure in NI. In 1994, Dr. Uday Limaye, Lecturer in radiology joined for training
in INR.
After Karapurkar took voluntary retirement from KEM Hospital, Seth GS Medical College
in 1996, Limaye took over NI at KEM Hospital with the strong support of Prof. S. K.
Pandya, HOD neurosurgery. Subsequently, he built up the best department of NI in the
country. He trained several radiologists and clinicians in the art and science of
NI.
Karapurkar moved to Indraprastha Apollo Hospital, New Delhi, and worked there from
1996 to 2002. He trained Dr. Harsh Rastogi, Radiologist, who continues to provide
NI services to the Apollo Hospital.
In 2002, Karapurkar moved back to Mumbai. He worked from 2002 to 2007 at Bombay Hospital,
2007 to 2011 at H N hospital, and 2009 onwards till date at Breach Candy Hospital.
From 2002 onwards he trained several neurologists, neurosurgeons, and radiologists.
There was a 3-month observership program which ran from 2002 to 2010. Since 2008,
Fellows are being taken for training in NI with the training period being 2 years.
Dr. Anand Alurkar, Neurologist, who trained from 2002 to 2003 has been training neurologists
since many years.
He trained many radiologists, neurologists, and neurosurgeons Later on, Dr. Shakir
Hussain in 1999 trained at Zurich under Prof. Anton Valavanis who began NI in Delhi.
Both of them started training young generations of neurosurgeons and neurologists
in neurointerventional procedures but it was slow, painful, and, during those times,
difficult to convince fellow clinicians to take NI as fulltime specialization.
NI was being practiced in the late 70s at only three places in India—KEM Hospital
& Seth GSMC, Mumbai, Dr. V. R. K. Rao at Sri Chitra Thirunal Institute, Trivandrum,
and Dr. N. K. Mishra, AIIMS, Delhi. At NIMHANS Bangalore, NI started in the late 80s.
Other institutions such as PGI Chandigarh, SGPGI Lucknow started in the nineties and
thereafter. SRMC, Chennai, under Prof. Santhosh Joseph started post 2002. In 1987,
Prof. B. Y. T. Arya of NIMHAS, Bangalore, went to Nancy in order to undergo training
under Prof. Picard. Dr. Jayakumar, also of NIMHANS, went to Nancy in the late 80s.
Prof. V. R. K. Rao was also supposed to go to Nancy but could not because of some
problems with visa.
Although there is lot of noise among young neurosurgeons regarding NI today, one cannot
ignore the fact that NI’s present form is because of some of the pioneering work done
and dedication shown by neuroradiologists like Prof. Lasjaunias, Prof. Jacques Moret,
Prof. Laurent Pierot, and Prof. Anton Valavanis who not only contributed to techniques
and technology but also trained future generations of neuroscientists across continents,
without any bias between neurosurgeon, neuroradiologist, or neurologist.
Conflict (Present)
Considerable progress has been made in NI in the last decade than in any of the previous
years. Many neurosurgeons now, especially the young, have got attracted to this branch
as a promising career option or addition to their neurosurgical skills. In India,
neuroradiologists or personnel with radiology background constitute the major work
force, approximately 60%, in NI, followed by neurosurgeons (30%), and neurologists
trained in neuroendovascular procedures (10%). Although these demographics are changing
rapidly with increase in number of neurosurgeons and neurologists, the majority are
either not trained or are “fly by night” or “one night” neurointerventionists being
proctored by nonmedical industry people driven by market forces, ignoring the fact
there is human cost involved in this. It is like clipping an aneurysm without knowing
how to do proper craniotomy, forgetting that minimally invasive nature of treatment
cannot reverse or decrease the severity of pathology. Adding to this already constrained
space, of which approximately 15 to 20% of all neurosurgical cases constitute vascular
cases,[25] cardiologists calling themselves “neurocardiologist” are also pitching in with reasons
like already trained in hardwares of catheters and wires. This statement has two flaws:
one may be that a cardiothoracic surgeon, or for that matter any surgeon, trained
to handle scalpel can become a neurosurgeon by the above logic and second, principle
of modern medicine is based on imparting knowledge of specialty-wise pathology and
treatment rather than studying the hardwares.
The biggest advantage of neurosurgeons, learning both clipping and performing NI,
is also its biggest disadvantage, according to me. Although decision-making to clip
or coil may be easy or sometimes biased also, but still because of alternative option
to clip, mastering to coil may be hampered, and hence majority end up being both clipper
and coiler—a hybrid neurosurgeon—which is the increasing trend. In public sector hospitals
or institutes, it may be possible to do so, but in private I do not think one can
have sufficient patients to justify being able to do clipping and coiling equally
good. The only advantage, according to me, of being a neurosurgeon doing NI is to
provide a honest and unbiased opinion about the mode of treatment. But NI in today’s
world is not coiling only; it is way beyond that and to become a fulltime neurointerventionist
in itself is a satisfying opportunity.
Neurointerventional Training (Future)
The best way to train is to include NI as a part of neurosurgical residency training.
But given the current situation, most of the institutes lack this facility to train
neurosurgical trainees. Therefore, as a starting point, at least rotational posting
in the neuroradiology department could be made compulsory for cerebral digital subtraction
angiography (DSA), which will prove to be a herculean task. As a matter of fact, this
will give future neurosurgeons some idea whether to pursue the dream or goal of NI,
instead of following the herd mentality of glamorous and upcoming subspecialty. There
are numerous guidelines from different societies regarding how to train future generations
of neurointerventionists. Most of the societies agree on starting with a minimum of
100 cerebral angiograms as first operator before starting with NI procedures based
on Connors review of cognitive and technical demands of cervicocerebral angiography.[26]
[27]
[28] Then, there is the duration of training from a minimum of 12 months to 24 months.[27] The duration of the training period of 2 years is endorsed by both Indian bodies
of NI, namely, Society of NeuroVascular Interventions (SNVI) and Society of Therapeutic
NeuroIntervention (STNI) along with requisite numbers of procedure. Most of the Western
societies asked to prolong the training period if the trainee did not complete the
defined number of procedures.
A month back, I conducted an informal survey among neurosurgeons to determine the
duration of NI training post M.Ch. Although the result varied from 15 days to 2 years,
but the majority agreed on at least a year of structured training.
Along with duration of training and number of procedures needed to train, there is
one very important aspect which both these societies forget to mention in their draft
training module, that is, radiation safety which is among the poorest in clinicians.
Also, there should be a minimum standard of equipment required to perform NI like
flat panel high resolution image intensifier cath laboratory, with road map fluoroscopy,
and, if possible, simultaneous real-time unsubstracted flouroscopy and three-dimensional
rotational angiography with on-spot CT (dyna CT for Seimens and XpertCT for Philips)
facility.[29]
