U.S. patent application number 11/047233 was filed with the patent office on 2005-06-16 for method and system for providing electrical pulses to gastric wall of a patient with rechargeable implantable pulse generator for treating or controlling obesity and eating disorders.
Invention is credited to Boveja, Birinder R., Widhany, Angely.
Application Number | 20050131487 11/047233 |
Document ID | / |
Family ID | 34704997 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050131487 |
Kind Code |
A1 |
Boveja, Birinder R. ; et
al. |
June 16, 2005 |
Method and system for providing electrical pulses to gastric wall
of a patient with rechargeable implantable pulse generator for
treating or controlling obesity and eating disorders
Abstract
Method and system for providing electrical pulses to the gastric
wall of a patient to provide therapy for obesity/eating disorders
comprises implantable and external components. The implantable
components are a lead and rechargeable implantable pulse generator,
comprising rechargeable lithium-ion or lithium-ion polymer battery.
The external components are a programmer and an external recharger.
In one embodiment, the implanted pulse generator may also comprise
stimulus-receiver means, and a pulse generator means with
rechargeable battery. The rechargeable implanted pulse generator of
this embodiment is also adapted to work in conjunction with an
external stimulator. In another embodiment, the implanted pulse
generator is adapted to be rechargeable, utilizing inductive
coupling with an external recharger. Existing gastric stimulators
may also be adapted to be used with rechargeable power sources as
disclosed herein. The implanted system may also use a lead with two
or more electrodes, for selective stimulation and/or blocking. In
another embodiment, the external stimulator and/or programmer may
comprise an optional telemetry unit. The addition of the telemetry
unit to the external stimulator and/or programmer provides the
ability to remotely interrogate and change stimulation programs
over a wide area network, as well as other networking
capabilities.
Inventors: |
Boveja, Birinder R.;
(Milwaukee, WI) ; Widhany, Angely; (Milwaukee,
WI) |
Correspondence
Address: |
BIRINDER R. BOVEJA & ANGELY WIDHANY
P. O. BOX 210095
MILWAUKEE
WI
53221
US
|
Family ID: |
34704997 |
Appl. No.: |
11/047233 |
Filed: |
January 31, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11047233 |
Jan 31, 2005 |
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11035374 |
Jan 13, 2005 |
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11035374 |
Jan 13, 2005 |
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10841995 |
May 8, 2004 |
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10841995 |
May 8, 2004 |
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10196533 |
Jul 16, 2002 |
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10196533 |
Jul 16, 2002 |
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10142298 |
May 9, 2002 |
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Current U.S.
Class: |
607/40 ;
607/58 |
Current CPC
Class: |
A61N 1/36114 20130101;
A61N 1/3627 20130101; A61N 1/36071 20130101; A61N 1/36007 20130101;
A61N 1/40 20130101; A61N 1/36082 20130101 |
Class at
Publication: |
607/040 ;
607/058 |
International
Class: |
A61N 001/18 |
Claims
What is claimed is:
1. A method of providing electrical pulses with rechargeable
implantable pulse generator at one or more sites to the gastric
wall of a patient for treating, controlling or alleviating the
symptoms for at least one of obesity, inducing weight loss, eating
disorders, obsessive compulsive disorders, and motility disorders,
comprising the steps of: providing said rechargeable implantable
pulse generator, comprising a microcontroller, pulse generation
circuitry, rechargeable battery, battery recharging circuitry, and
a coil; providing a lead with at least two electrodes adapted to be
in contact with said gastric wall of a patient, and in electrical
contact with said rechargeable implantable pulse generator;
providing an external power source to charge said rechargeable
implantable pulse generator; and providing an external programmer
to program said rechargeable implantable pulse generator.
2. A method of claim 1, wherein said coil used in recharging said
pulse generator is around said implantable rechargeable pulse
generator case, in a silicone enclosure.
3. A method of claim 1, wherein said implantable rechargeable pulse
generator does not require magnetic shielding between said coil and
said titanium case.
4. A method of claim 1, wherein said rechargeable implanted pulse
generator further comprises one or two feed-through(s) for unipolar
or bipolar configurations respectively.
5. A method of claim 1, wherein said implantable rechargeable pulse
generator further comprises stimulus-receiver means such that, said
implantable rechargeable pulse generator can function in
conjunction with an external stimulator, to provide said electrical
pulses to said gastric wall of a patient.
6. A method of claim 1, wherein said rechargeable battery comprises
at least one of lithium-ion, lithium-ion polymer batteries.
7. The method of claim 1, wherein the amplitude of said electrical
pulses delivered to the gastric wall can range from 0.5 volt to 25
volts.
8. The method of claim 1, wherein the pulse width of said
electrical pulses delivered to the gastric wall can range from 5
milliseconds to 2 seconds.
9. The method of claim 1, wherein the frequency of said electrical
pulses delivered to the gastric wall can range from 1 cycle/min. to
100 cycles/min.
10. The method of claim 1, wherein said rechargeable implanted
pulse generator is adapted to be remotely interrogated and/or
programmed over a wide area network by an external interface
means.
11. A method of providing pulsed electrical therapy to gastric
muscle wall for treating or controlling at least one of eating
disorders, obesity, or inducing weight loss in a patient,
comprising the steps of: providing an implantable rechargeable
pulse generator, wherein said rechargeable implantable pulse
generator comprises a stimulus-receiver means, and an implantable
pulse generator means, comprising a microcontroller, pulse
generation circuitry, rechargeable battery, and battery recharging
circuitry; providing a lead with at least two electrodes adapted to
be in contact with said vagus nerve(s) or its branches or part
thereof, and in electrical contact with said implantable
rechargeable pulse generator; providing an external power source to
charge rechargeable implantable pulse generator; and providing an
external programmer to program the said rechargeable implantable
pulse generator, whereby said electric pulses provide said
therapy.
12. A method of claim 11, wherein said rechargeable implantable
pulse generator can be recharged using an external re-charger or an
external stimulator.
13. A method of claim 11, wherein said rechargeable battery
comprises at least one of lithium-ion, lithium-ion polymer
batteries.
14. A system for providing electrical pulses at one or more sites
to the gastric wall of a patient for treating, controlling or
alleviating the symptoms for at least one of obesity, inducing
weight loss, eating disorders, obsessive compulsive disorders, and
motility disorders, comprising: a rechargeable implantable pulse
generator, comprising, a microprocessor, pulse generation
circuitry, rechargeable battery, battery recharging circuitry, and
a coil; a lead with at least two electrodes adapted to be in
contact with the gastric wall in a patient and in electrical
contact with said implantable rechargeable pulse generator; an
external power source to charge said rechargeable implantable pulse
generator; and an external programmer to program said rechargeable
implantable pulse generator.
15. A system of claim 14, wherein the amplitude of said electrical
pulses delivered to the gastric wall can range from 0.5 volt to 25
volts.
16. A system of claim 14, wherein the pulse width of said
electrical pulses delivered to the gastric wall can range from 5
milliseconds to 2 seconds.
17. A system of claim 14, wherein the frequency of said electrical
pulses delivered to the gastric wall can range from 1 cycle/min. to
100 cycles/min.
18. A system of claim 14, wherein said rechargeable battery
comprises at least one of lithium-ion, lithium-ion polymer
batteries.
19. A system of claim 14, wherein said coil is used for
bi-directional telemetry, or receiving electrical pulses from said
external stimulator.
20. A system of claim 14, wherein said coil used in recharging said
pulse generator is around said rechargeable implantable pulse
generator case in a silicone enclosure.
21. A system of claim 14, wherein said rechargeable implanted pulse
generator further comprises one or two feed-through(s) for unipolar
or bipolar configurations respectively.
22. A system of claim 14, wherein said implantable rechargeable
pulse generator further comprises stimulus-receiver means such that
said implantable rechargeable pulse generator can also function in
conjunction with an external stimulator, to provide said electrical
pulses to said gastric wall of a patient.
23. A system of claim 14, wherein said at least two electrodes are
of a material selected from the group consisting of platinum,
platinum/iridium alloy, platinum/iridium alloy coated with titanium
nitride, and carbon.
24. A system of claim 14, wherein said rechargeable implanted pulse
generator is adapted to be remotely interrogated and/or programmed
over a wide area network by an external interface means.
Description
[0001] This application is a continuation of application Serial No.
11/035,374 filed Jan. 13, 2005, entitled "Method and system for
providing electrical pulses for neuromodulation of vagus nerve(s)
using rechargeable implanted pulse generator", which is a
continuation of application Ser. No. 10/841,995 filed May 8, 2004,
which is a continuation of application Ser. No. 10/196,533 filed
Jul. 16, 2002, which is a continuation of application Ser. No.
10/142,298 filed on May 9, 2002. The prior applications being
incorporated herein in entirety by reference, and priority is
claimed from these applications.
FIELD OF INVENTION
[0002] This invention relates generally to electrical stimulation
therapy for gastrointestinal (GI) disorders, more specifically to
gastric myo-electrical pacing therapy for obesity and eating
disorders with rechargeable implantable pulse generator.
BACKGROUND
[0003] Obesity is a significant health problem in the United States
and many other developed countries. Obesity results from excessive
accumulation of fat in the body. It is caused by ingestion of
greater amounts of food than can be used by the body for energy.
The excess food, whether fats, carbohydrates, or proteins, is then
stored almost entirely as fat in the adipose tissue, to be used
later for energy. Obesity is not simply the result of gluttony and
a lack of willpower. Rather, each individual inherits a set of
genes that control appetite and metabolism, and a genetic tendency
to gain weight that may be exacerbated by environmental conditions
such as food availability, level of physical activity and
individual psychology and culture. Other causes of obesity include
psychogenic, neurogenic, and other metabolic related factors.
[0004] Obesity is defined in terms of body mass index (BMI), which
provides an index of the relationship between weight and height.
The BMI is calculated as weight (in Kilograms) divided by height
(in square meters), or as weight (in pounds) times 703 divided by
height (in square inches). The primary classification of overweight
and obesity relates to the BMI and the risk of mortality. The
prevalence of obesity in adults in the United States without
coexisting morbidity increased from 12% in 1991 to 17.9% in
1998.
[0005] Treatment of obesity depends on decreasing energy input
below energy expenditure. Treatment has included among other things
various drugs, starvation and even stapling or surgical resection
of a portion of the stomach. Surgery for obesity has included
gastroplasty and gastric bypass procedure. Gastroplasty which is
also known as stomach stapling, involves constructing a 15- to 30
mL pouch along the lesser curvature of the stomach. A modification
of this procedure involves the use of an adjustable band that wraps
around the proximal stomach to create a small pouch. Both
gastroplasty and gastric bypass procedures have a number of
complications.
[0006] This Application discloses a method and system for providing
gastric myo-electric pulses to the stomach wall using an implanted
gastric lead and a rechargeable implantable pulse generator (FIGS.
10 and 11). Such gastric pacing disrupts the normal gastric
motility and provides therapy to an obese patient. Advantageously,
such disruption of the normal gastric motility is reversible,
unlike gastric bypass surgery. Details of such system and method
are disclosed in this Application.
Background of Gastrointestinal (GI) Physiology and Regulation
[0007] Shown in conjunction with FIG. 1, the gastrointestinal (GI)
tract is a continuous muscular digestive tube that winds through
the body. The organs of the GI tract are the mouth, pharynx (not
shown), esophagus 3, stomach 54, small intestine (duodenum 7,
jejunum, and ileum), and large intestine (cecum, ascending colon,
transverse colon, and descending colon).
[0008] The gastrointestinal (GI) tract has a nervous system all its
own, which is the enteric nervous system 21. This is shown in
conjunction with FIG. 2. It lies entirely in the wall of the gut,
beginning in the esophagus 3 and extending all the way to the anus.
The enteric nervous system has about 100 million neurons, almost
exactly equal to the number in the entire spinal cord. It
especially controls gastrointestinal movements and secretion. The
enteric nervous system is composed mainly of the two plexuses, 1)
the myenteric plexus 22, which is the outer plexus lying between
the longitudinal and circular muscle layers, and 2) the submucosal
plexus 23 that lies in the submucosa. The nervous connection within
and between these two plexuses is depicted in FIG. 2. The myenteric
plexus controls mainly the gastrointestinal movements, and the
submucosal plexus controls mainly gastrointestinal secretion and
local blood flow. As also depicted in FIG. 2, the sympathetic and
parasympathetic fibers connect with the myenteric 22 and the
submocosal 23 plexus. Although the enteric nervous system can
function on its own, stimulation by the parasympathetic 25 and
sympathetic 26 systems can further activate or inhibit
gastrointestinal functions. The autonomic nerves influence the
functions of the gastrointestinal tract by modulating the
activities of neurons of the enteric nervous system 21.
[0009] Shown in conjunction with FIGS. 2 and 3, sympathetic
innervation of the gastrointestinal tract is mainly via
postganglionic adrenergic fibers whose cell bodies are located in
pre-vertebral and parabertabral ganglia. The celiac, superior and
inferior mesenteric, and hypogastric plexus provide sympathetic
innervation to various segments of the GI tract. Activation of the
sympathetic nerves usually inhibits the motor and secretory
activities of the GI system.
[0010] Parasympathetic innervation of the GI tract down to the
level of the transverse colon is provided by branches of the vagus
nerves (10.sup.th cranial nerve). Excitation of parasympathetic
nerves usually stimulates the motor and secretory activities of the
GI tract.
[0011] The stomach 54 is richly innervated by extrinsic nerves and
by the neurons of the enteric nervous system 21. Axons from the
cells of the intramural plexus innervate smooth muscle and
secretory cells.
[0012] The emptying of gastric contents is regulated by both neural
and hormonal mechanisms. The duodenal and jejunal mucosa contain
receptors that sense acidity, osmotic pressure, certain fats and
fat digestion products, and peptides and amino acids This is
depicted in FIG. 4. The chyme that leaves the stomach is usually
hypertonic and it becomes even more hypertonic because of the
action of the digestive enzymes in the duodenum. Gastric emptying
is slowed by hypertonic solutions in the duodenum, by duodenal pH
below 3.5, and by the presence of amino acids and peptides in the
duodenum, The presence of fatty acids or monoglycerides (products
of fat digestion) in the duodenum also dramatically decreases the
rate of gastric emptying.
[0013] Parasympathetic innervation to the stomach is supplied by
the vagus nerves, while sympathetic innervation to the stomach is
provided by the celiac plexus. In general, parasympathetic nerves
stimulate gastric smooth muscle motility and gastric secretions,
whereas sympathetic activity inhibits these function. Numerous
sensory afferent fibers leave the stomach in the vagus nerves; some
of these fibers travel with sympathetic nerves. Other sensory
neurons are the afferent links between sensory receptors and the
intramural plexuses of the stomach. Some of these afferent fibers
relay information intragastric pressure, gastric distention,
intragastric pH, or pain.
[0014] Shown in conjunction with FIG. 5 is the fundus 15, the body
17, and antrum 19 of the stomach 54. After eating, when a wave of
esophageal peristalsis begins, a reflex causes the LES to relax.
This relaxation of the LES is followed by receptive relaxation of
the fundus 15 and body 17 of the stomach. The stomach 54 will also
relax if it is filled directly with gas or liquid. The nerve fibers
in the vagi are a major efferent pathways for reflex relaxation of
the stomach 54.
[0015] FIG. 6 depicts the three main muscle layers of the stomach
54, which are the longitudinal layer 14, the circular layer 16, and
the oblique layer 18. The complex and coordinated activity of these
muscle layers is responsible for the normally efficient gastric
motility. Whereas, the gastric pacing disclosed here from around
the antral area of the stomach 54, disrupts the normal gastric
motility.
[0016] Normally, the smooth muscle of the GI tract is excited by
almost continual slow, intrinsic electrical activity along the
membranes of the muscle fibers. This activity has two basic types
of electrical waves: 1) slow waves and 2) spikes. This is shown in
conjunction with FIG. 7. Most gastrointestinal contractions occur
rhythmically, and this rhythm is determined mainly by the frequency
of the slow waves of the smooth muscle membrane potential. Their
intensity usually varies between 5 and 15 millivolts, and their
frequency ranges in different parts of the human gastrointestinal
tract between 3 and 12 per minute. The rhythm of contraction of the
body of the stomach is about 3 per minute (and in the duodenum is
about 12 per minute).
[0017] The electrical activity of the GI tract is shown in
conjunction with FIG. 7. For example, the contraction of small
intestinal smooth muscle occurs when the depolarization caused by
the slow wave exceeds a threshold for contraction. When
depolarization of a slow wave exceeds the electrical threshold, a
burst of action potentials 29 occurs. The action potentials elicit
a much stronger contraction than occurs in the absence of action
potentials. The contractile force increases with increasing number
of action potentials.
[0018] Action potentials in gastrointestinal smooth muscle are more
prolonged (10 to 20 msec) than those of skeletal muscle and have
little or no overshoot. The rising phase of the action potentials
is caused by ion flow through channels that conduct both Ca.sup.++
and Na.sup.+ and are relatively slow to open. Ca.sup.++ that enters
the cell during the action potential helps to initiate
contraction.
[0019] When the membrane potential of gastrointestinal smooth
muscle reaches the electrical threshold, typically near the peak of
a slow wave, a train of action potentials (1 to 10/sec) is fired.
The extent of depolarization of the cells and the frequency of
action potentials are enhanced by some hormones and paracrine
agonists and by compounds liberated from excitatory nerve endings.
Inhibitory hormones and neuroefector substances hyperpolarize the
smooth muscle cells and may diminish or abolish action potential
spikes.
[0020] Slow waves that are not accompanied by action potentials
elicit weak contractions of the smooth muscle cells (FIG. 7). Much
stronger contractions are evoked by the action potentials that are
intermittently triggered near the peaks of the slow waves. The
greater the frequency of action potentials that occur at the peak
of a slow wave, the more intense is the contraction of the smooth
muscle. Because smooth muscle cells contract rather slowly (about
one tenth as fast as skeletal muscle cells), the individual
contraction caused by each action potential in a train do not cause
distinct twitches; rather, they sum temporally to produce a
smoothly increasing level of tension (FIG. 7).
[0021] Between trains of action potentials the tension developed by
gastrointestinal smooth muscle falls, but not to zero. This nonzero
resting, or baseline, tension of smooth muscle is called tone. The
tone of gastrointestinal smooth muscle is altered by
neuroeffectors, hormones, paracrine substances, and drugs.
[0022] Control of the contractile and secretory activities of the
gastrointestinal tract involves the central nervous system, the
enteric nervous system, and hormones and paracrine substances. The
autonomic nervous system typically only modulates the patterns of
muscular and secretary activity; these activities are controlled
more directly by the enteric nervous system.
[0023] In the current invention, as shown in conjunction with FIG.
8, a lead and a rechargeable implantable pulse generator is
surgically implanted in the body. By stimulating the stomach wall
with the system described in this disclosure, using a site and
frequency which competes with the intrinsic rhythm, the normal
gastric motility is interfered with, and general decrease of normal
gastric motility occurs. The stomach is empties less
efficiently.
[0024] Shown in conjunction with FIG. 9, with the stomach not
emptying as efficiently, satiety signals which are sent to the
brain (via the vagus nerves), make the patients feel less hungry.
With the capacity to handle less food through the GI tract, and at
the same time the patients feeling less hungry, therapy is provided
for obesity and weight loss. Advantageously, in the method and
system of this invention, this process is controllable and
reversible utilizing an implanted lead and a programmable
rechargeable implantable pulse generator.
[0025] This application is also related to co-pending applications
entitled "METHOD AND SYSTEM FOR VAGAL BLOCKING WITH OR WITHOUT
VAGAL STIMULATION TO PROVIDE THERAPY FOR OBESITY AND OTHER
GASRTOINTESTINAL DISORDERS USING RECHARGEABLE IMPLANTED PULSE
GENERATOR", and "METHOD AND SYSTEM TO PROVIDE THERAPY FOR OBESITY
AND OTHER MEDICAL DISORDERS, BY PROVIDING ELECTRICAL PULSES TO
SYMPATHETIC NERVES OR VAGAL NERVE(S) WITH RECHARGEABLE IMPLANTED
PULSE GENERATOR".
PRIOR ART
[0026] Prior art is generally directed to adapting cardiac
pacemaker technology to gastric pacing. But, the requirements of
gastric pacing are significantly different from those of cardiac
pacing.
[0027] U.S. Pat. No. 6,615,084 (Cigaina) is generally directed to a
process of using electrostimulation for treating obesity. An
implantable pulse generator (similar to cardiac pacemaker) appears
to be used even though details are not provided for stimulation
technology.
[0028] U.S. Pat. No. 5,423,872 (Cigaina) is also generally directed
to a process for treating obesity and syndromes related to motor
disorders of the stomach. There is no disclosure or suggestion for
an inductively coupled system with an implanted stimulus-receiver
and an external stimulator for supplying the electrical pulses, or
for recharging an implantable system.
[0029] U.S. Pat. No. 5,690,691 (Chen et al.) is generally directed
to a gastric pacemaker having phased multi-point stimulation. This
disclosure is aimed primarily at having multiple electrodes
throughout the gastrointestinal tract and providing phased
electrical stimulation to either enhance or attenuate the
peristaltic movement to treat eating disorders or diarrhea.
[0030] U.S. Pat. No. 6,321,124 B1 (Cigaina) is generally directed
to the implantable lead aspect of a gastrointestinal pacing
system.
[0031] U.S. Pat. No. 6,104,955 (Bourgeois) and U.S. Pat. No.
5,861,014 (Familoni) are generally directed to pulse generator
systems featuring sensors for sensing gastric electrical activity,
and pacing capabilities.
[0032] U.S. Pat. No. 6,553,263B1 (Meadows et al.) is generally
directed to an implantable pulse generator system for spinal cord
stimulation, which includes a rechargeable battery. In the Meadows
'263 patent there is no disclosure or suggestion for combing a
stimulus-receiver module to an implantable pulse generator (IPG)
for use with an external stimulator, for providing modulating
pulses to sympathetic nerve(s), as in the applicant's
disclosure.
[0033] U.S. Pat. No. 6,505,077 B1 (Kast et al.) is directed to
electrical connection for external recharging coil. In the Kast
'077 disclosure, a magnetic shield is required between the
externalized coil and the pulse generator case. In one embodiment
of the applicant's disclosure, the externalized coil is wrapped
around the pulse generator case, without requiring a magnetic
shield.
[0034] U.S. Pat. No. 6,611,715 B1 (Boveja) is generally directed to
a system and method to provide therapy for obesity and compulsive
eating disorders using an implantable lead-receiver and an external
stimulator.
[0035] The method and system of the current disclosure is
advantageous because it provides an ideal power source. The high
output requirements of gastric pacing (which are met by high
amplitude pulses and very long pulse duration (compared to cardiac
pacing) are ideally met by the system and method of the current
disclosure. This system is advantageous because it eliminates
repeated surgeries which are required for subcutaneously implanted
pulse generator changes. Additional advantage of the system and
method of the current disclosure is that the external stimulator
can be remotely interrogated and programmed over the internet. This
eliminates the need for patient to visit physician's office or
clinic every time the device needs to be programmed.
SUMMARY OF THE INVENTION
[0036] The method and system of the current invention overcomes
many shortcomings of the prior art by providing a system for
providing pulses to gastric wall with extended power source either
in the form of rechargeable battery, or by utilizing an external
stimulator in conjunction with an implanted pulse generator device,
to provide therapy for obesity, eating disorders or for inducing
weight loss.
[0037] Accordingly, in one aspect of the invention, electrical
pulses are provided to gastric wall utilizing a rechargeable
implantable pulse generator.
[0038] In another aspect of the invention, the electrical pulses to
the gastric wall are provided for at least one of obesity, inducing
weight loss, eating disorders, obsessive compulsive disorders, and
motility disorders.
[0039] In another aspect of the invention, the pulse amplitude
delivered to sympathetic nervous system can range from 0.25 volt to
25 volts.
[0040] In another aspect of the invention, the pulse width of
electrical pulses delivered can range from 5 milli-seconds to 2
seconds.
[0041] In another aspect of the invention, the frequency of
electrical pulses delivered to sympathetic nervous system can range
from 1 cycle/second to 100 cycles/second.
[0042] In another aspect of the invention, a coil used in
recharging said pulse generator is around the implantable pulse
generator case, and in a silicone enclosure.
[0043] In another aspect of the invention, the rechargeable
implanted pulse generator comprises two feedthroughs.
[0044] In another aspect of the invention, the rechargeable
implanted pulse generator comprises only one feedthrough for
externalizing the recharge coil.
[0045] In another aspect of the invention, the implantable
rechargeable pulse generator comprises stimulus-receiver means such
that, the implantable rechargeable pulse generator can function in
conjunction with an external stimulator, to provide the stimulation
and/or blocking pulses to the gastric wall of a patient.
[0046] In another aspect of the invention, the rechargeable battery
comprises at least one of lithium-ion, lithium-ion polymer
batteries.
[0047] In another aspect of the invention, the external programmer
or the external stimulator comprises networking capabilities for
remote communications over a wide area network for remote
interrogation and/or remote programming.
[0048] In yet another aspect of the invention, the implanted lead
comprises at least one electrode(s) which is/are made of a material
selected from the group consisting of platinum, platinum/iridium
alloy, platinum/iridium alloy coated with titanium nitride, and
carbon.
[0049] These and other objects are provided by one or more of the
embodiments described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] For the purpose of illustrating the invention, there are
shown in accompanying drawing forms which are presently preferred,
it being understood that the invention is not intended to be
limited to the precise arrangement and instrumentalities shown.
[0051] FIG. 1 is a diagram showing general anatomy of the
gastrointestinal (GI) tract.
[0052] FIG. 2 is a diagram showing control of the enteric nervous
system by the autonomic nervous system (parasympathetic and
sympathetic).
[0053] FIG. 3 is a simplified diagram depicting sympathetic and
parasympathetic innervation of the gastrointestinal (GI) tract.
[0054] FIG. 4 is a diagram depicting control of gastric emptying by
the sympathetic and parasympathetic activity.
[0055] FIG. 5 is a diagram showing general anatomy of the human
stomach.
[0056] FIG. 6 is a diagram showing the longitudinal, circular, and
oblique muscle layers of the stomach.
[0057] FIG. 7 is a diagram depicting the electrical activity of the
GI tract.
[0058] FIG. 8 is a diagram showing the implanted components of the
invention.
[0059] FIG. 9 is a schematic diagram showing the relationship of
meals and satiety signals.
[0060] FIGS. 10 and 11 are diagrams showing the implanted
components of the invention, which are a lead and rechargeable
implanted pulse generator.
[0061] FIG. 12 is a simplified general block diagram of an
implantable pulse generator.
[0062] FIG. 13A shows energy density of different types of
batteries.
[0063] FIG. 13B shows discharge curves for different types of
batteries.
[0064] FIG. 14 shows a block diagram of an implantable device which
can be used as a stimulus-receiver or an implanted pulse generator
with rechargeable battery.
[0065] FIG. 15 is a block diagram highlighting battery charging
circuit of the implantable stimulator of FIG. 14.
[0066] FIG. 16 is a schematic diagram highlighting
stimulus-receiver portion of implanted stimulator of one
embodiment.
[0067] FIG. 17 depicts externalizing recharge and telemetry coil
from the titanium case.
[0068] FIG. 18A depicts coil around the titanium case with two
feedthroughs for a bipolar configuration.
[0069] FIG. 18B depicts coil around the titanium case with one
feedthrough for a unipolar configuration.
[0070] FIG. 18C depicts two feedthroughs for the external coil
which are common with the feedthroughs for the lead terminal.
[0071] FIG. 18D depicts one feedthrough for the external coil which
is common to the feedthrough for the lead terminal.
[0072] FIGS. 19A and 19B depict recharge coil on the titanium case
with a magnetic shield in-between.
[0073] FIG. 20 shows an implantable rechargable pulse generator in
block diagram form.
[0074] FIG. 21 depicts in block diagram form, the implanted and
external components of an implanted rechargable system.
[0075] FIG. 22 depicts the alignment function of rechargable
implantable pulse generator.
[0076] FIG. 23 is a block diagram of the external recharger.
[0077] FIG. 24A is a schematic diagram of the implantable lead with
two electrodes.
[0078] FIG. 2B is a schematic diagram of the implantable lead with
three electrodes.
[0079] FIG. 25 is a schematic diagram depicting external stimulator
and two-way communication through a server.
[0080] FIG. 26 is a diagram depicting wireless remote interrogation
and programming of the external stimulator.
[0081] FIG. 27 is a schematic diagram depicting wireless
protocol.
[0082] FIG. 28 is a simplified block diagram of the networking
interface board.
[0083] FIGS. 29A and 29B are simplified diagrams showing
communication of modified PDA/phone with an external stimulator via
a cellular tower/base station.
DESCRIPTION OF THE INVENTION
[0084] In the method and system of this invention, a lead 40
comprising at least one pair of electrodes for providing gastric
myo-electrical stimulation is laprscopically implanted in a
patient. In one preferred procedure methodology, a patient
undergoing general endotracheal anesthesia is positioned in
lithotomy position. A minimum of three trocars are inserted. A
midline supraumbilical port is used to introduce the optical
system. Another port is used to introduce the stomach grasper. One
other port (a subcostal port) is used to introduce the lead and
subsequently the needle-driver. The back end of the lead is brought
out through this left subcostal port at the completion of the
abdominal portion of the operation.
[0085] The lead is then introduced into the abdomen, and inserted
into a muscle tunnel. Using appropriate counter-traction on the
stomach, both of the electrodes are ensured to be buried within the
tunnel wall. After the electrodes have been inserted, a flexible
fiberoptic gastroscopy is performed to ensure that inadvertent
perforation of the needle into the lumen of the stomach has not
occurred. Once the lead is satisfactorily implanted, it is secured
in position with non-absorbable suture. A pocket is prepared on the
anterior abdominal wall, and the rechargeable implantable pulse
generator is implanted subutaneously. The skin is surgically closed
in the usual manner. The electrical stimulation to the gastric wall
can begin once the patient is completely healed from the
surgery.
[0086] Shown in conjunction with FIGS. 8, 10, and 11, the pulses
are typically provided via lead 40 between electrodes 61 and 62,
for a bipolar configuration. A unipolar configuration can also be
used where the pulse generator case is used as the ground
electrode, i.e. the pulses are provided between electrode 61 and
the case. The stimulation of the gastric muscle can be performed in
one of two ways. One method is to activate one of several stored
"pre-determined" programs. A second method is to "custom" program
the electrical parameters which can be selectively programmed, for
specific therapy to the individual patient. Additionally, if a
stored program is used, it can be further adjusted or "fine tuned"
by modifying any programmable parameter. The electrical parameters
that can be individually modified or programmed, include variables
such as pulse amplitude, pulse width, frequency of stimulation,
stimulation on-time, and stimulation off-time. Table one below
defines the approximate range of parameters;
1TABLE 1 Electrical parameter range delivered to the gastric wall
PARAMETER RANGE Pulse Amplitude 0.5 Volt to 25 Volts Pulse Width 5
msec. to 2 secs Frequency 1 cycle/min to 100 cycles/min On-time 1
min. to 24 hours Off-time 1 min. to 24 hours
[0087] The parameters in Table 1 are the electrical signals
delivered to the gastric wall tissue via the two electrodes 61,62
(distal and proximal) in the gastric wall.
[0088] Without limitation and by way of example only, Low, Medium,
and High output stimulation states stored in memory. For
example;
[0089] 1. LO Stim.
[0090] Amplitude--2.5 Volts
[0091] Pulse Width--200 msec
[0092] 2. MED Stim.
[0093] Amplitude--5 Volts
[0094] Pulse Width--350 msec
[0095] 3. HI Stim.
[0096] Amplitude--7.5 Volts
[0097] Pulse Width--500 msec
[0098] Once a LO, MED, or HI stimulation program is activated, each
individual parameter can be incremented up or down in small
increments, within the range defined in Table 1. When parameter
settings are found that work particularly well for the patient,
they can be stored in the memory of the device. Any number of these
"customized" programs can be stored in the memory of the pulse
generator.
[0099] Shown in conjunction with FIG. 12, is an overall schematic
of a conventional implantable pulse generator system to deliver
electrical pulses for stimulating the gastric wall and providing
therapy. The implantable pulse generator unit 391 NR is a
microprocessor based device, where the entire circuitry is encased
in a hermetically sealed titanium case. As shown in the overall
block diagram, the logic & control unit 398 provides the proper
timing for the output circuitry 385 to generate electrical pulses
that are delivered to a pair of electrodes via a lead 40. Timing is
provided by oscillator 393. The pair of electrodes to which the
stimulation energy is delivered is switchable. Programming of the
implantable pulse generator (IPG) is done via an external
programmer 85. Once programmed via an external programmer 85, the
implanted pulse generator 391 NR provides appropriate electrical
stimulation pulses to the gastric wall 54 via the stimulating
electrode pair 61,62. In this disclosure, the terms stomach,
gastric wall, and gastric wall muscle are used interchangeably.
Additional pulses may be provided for blocking, as described
later.
[0100] Because of the high energy requirements for the pulses
required for stimulating the gastric wall muscle 54 (unlike cardiac
pacing), there is a real need for power sources that will provide
an acceptable service life under conditions of continuous delivery
of high frequency pulses. FIG. 13A shows a graph of the energy
density of several commonly used battery technologies. Lithium
batteries have by far the highest energy density of commonly
available batteries. Also, a lithium battery maintains a nearly
constant voltage during discharge. This is shown in conjunction
with FIG. 13B, which is normalized to the performance of the
lithium battery. Lithium-ion batteries also have a long cycle life,
and no memory effect. However, Lithium-ion batteries are not as
tolerant to overcharging and overdischarging. One of the most
recent development in rechargable battery technology is the
Lithium-ion polymer battery. Recently the major battery
manufacturers (Sony, Panasonic, Sanyo) have announced plans for
Lithium-ion polymer battery production.
[0101] In the method of the current invention, two embodiments of
implantable pulse generators may be used. Both embodiments comprise
re-chargeable power sources, such as Lithium-ion polymer
battery.
[0102] In one embodiment, the implanted device comprises a
stimulus-receiver module and a pulse generator module.
Advantageously, this embodiment provides an ideal power source,
since the power source can be an external stimulator coupled with
an implanted stimulus-receiver, or the power source can be from the
implanted rechargeable battery. Shown in conjunction with FIG. 14
is a simplified overall block diagram of this embodiment. A coil
48C which is external to the titanium case may be used both as a
secondary of a stimulus-receiver, or may also be used as the
forward and back telemetry coil. The coil 48C may be externalized
at the header portion 79C of the implanted device, and may be
wrapped around the titanium case, eliminating the need for a
magnetic shield. In this case, the coil is encased in the same
material as the header 79C. Alternatively, the coil may be
positioned on the titanium case, with a magnetic shield.
[0103] In this embodiment, as shown in FIG. 14, the IPG circuitry
within the titanium case is used for all stimulation pulses whether
the energy source is the internal battery 740 or an external power
source. The external device serves as a source of energy, and as a
programmer that sends telemetry to the IPG. An external stimulator
and recharger may also be combined within the same enclosure. For
programming, the energy is sent as high frequency sine waves with
superimposed telemetry wave driving the external coil 46C. The
telemetry is passed through coupling capacitor 727 to the IPG's
telemetry circuit 742. For pulse delivery using external power
source, the stimulus-receiver portion will receive the energy
coupled to the implanted coil 48C and, using the power conditioning
circuit 726, rectify it to produce DC, filter and regulate the DC,
and couple it to the IPG's voltage regulator 738 section so that
the IPG can run from the externally supplied energy rather than the
implanted battery 740.
[0104] The system of this embodiment provides a power sense circuit
728 that senses the presence of external power communicated with
the power control 730, when adequate and stable power is available
from an external source. The power control circuit controls a
switch 736 that selects either implanted battery power 740 or
conditioned external power from 726. The logic and control section
732 and memory 744 includes the IPG's microcontroller,
pre-programmed instructions, and stored changeable parameters.
Using input for the telemetry circuit 742 and power control 730,
this section controls the output circuit 734 that generates the
output pulses.
[0105] Shown in conjunction with FIG. 15, this embodiment of the
invention is practiced with a rechargeable battery. This circuit is
energized when external power is available. It senses the charge
state of the battery and provides appropriate charge current to
safely recharge the battery without overcharging. Recharging
circuitry is described later.
[0106] The stimulus-receiver portion of the circuitry is shown in
conjunction with FIG. 16. Capacitor C1 (729) makes the combination
of C1 and L1 sensitive to the resonant frequency and less sensitive
to other frequencies, and energy from an external (primary) coil
46C is inductively transferred to the implanted unit via the
secondary coil 48C. The AC signal is rectified to DC via diode 731,
and filtered via capacitor 733. A regulator 735 sets the output
voltage and limits it to a value just above the maximum IPG cell
voltage. The output capacitor C4 (737), typically a tantalum
capacitor with a value of 100 micro-Farads or greater, stores
charge so that the circuit can supply the IPG with high values of
current for a short time duration with minimal voltage change
during a pulse while the current draw from the external source
remains relatively constant. Also shown in conjunction with FIG.
16, a capacitor C3 (727) couples signals for forward and back
telemetry.
[0107] In another embodiment, existing implantable pulse generators
can be modified to incorporate rechargeable batteries. As shown in
conjunction with FIG. 17, in both embodiments, the coil is
externalized from the titanium case 57. The RF pulses transmitted
via coil 46 and received via subcutaneous coil 48A are rectified
via a diode bridge. These DC pulses are processed and the resulting
current applied to recharge the battery 694/740 in the implanted
pulse generator. In one embodiment the coil 48C may be externalized
at the header portion 79 of the implanted device, and may be
wrapped around the titanium can, as shown in FIGS. 18A and 18B.
Shown in FIG. 18A is a bipolar configuration which requires two
feedthroughs 76,77. Advantageously, as shown in FIG. 18B unipolar
configuration may also be used which requires only one feedthrough
75. The other end is electronically connected to the case. In both
cases, the coil is encased in the same material as the header 79.
Advantageously, as shown in conjunction with FIGS. 18C and 18D, the
feedthrough for the coil can be combined with the feedthrough for
the lead terminal. This can be applied both for bipolar and
unipolar configurations.
[0108] In one embodiment, the coil may also be positioned on the
titanium case as shown in conjunction with FIGS. 19A and 19B. FIG.
19A shows a diagram of the finished implantable stimulator 391R of
one embodiment. FIG. 19B shows the pulse generator with some of the
components used in assembly in an exploded view. These components
include a coil cover 13, the secondary coil 48 and associated
components, a magnetic shield 9, and a coil assembly carrier 11.
The coil assembly carrier 11 has at least one positioning detail 80
located between the coil assembly and the feed through for
positioning the electrical connection. The positioning detail 80
secures the electrical connection in this embodiment.
[0109] A schematic diagram of the implanted pulse generator (IPG
391R) with re-chargeable battery 694 of the preferred embodiment of
this invention, is shown in conjunction with FIG. 20. The IPG 391R
includes logic and control circuitry 673 connected to memory
circuitry 691. The operating program and stimulation parameters are
typically stored within the memory 691 via forward telemetry.
Stimulation pulses are provided to the gastric muscle wall 54 via
output circuitry 677 controlled by the microcontroller.
[0110] The operating power for the IPG 391R is derived from a
rechargeable power source 694. The rechargeable power source 694
comprises a rechargeable lithium-ion or lithium-ion polymer
battery. Recharging occurs inductively from an external charger to
an implanted coil 48B underneath the skin 60. The rechargeable
battery 694 may be recharged repeatedly as needed. Additionally,
the IPG 391R is able to monitor and telemeter the status of its
rechargable battery 691 each time a communication link is
established with the external programmer 85.
[0111] Much of the circuitry included within the IPG 391R may be
realized on a single application specific integrated circuit
(ASIC). This allows the overall size of the IPG 391R to be quite
small, and readily housed within a suitable hermetically-sealed
case. The IPG case is preferably made from titanium and is shaped
in a rounded case.
[0112] Shown in conjunction with FIG. 21 are the recharging
elements of the invention. The re-charging system uses a portable
external charger to couple energy into the power source of the IPG
391R. The DC-to-AC conversion circuitry 696 of the re-charger
receives energy from a battery 672 in the re-charger. A charger
base station 680 and conventional AC power line may also be used.
The AC signals amplified via power amplifier 674 are inductively
coupled between an external coil 46B and an implanted coil 48B
located subcutaneously with the implanted pulse generator (IPG)
391R. The AC signal received via implanted coil 48B is rectified
686 to a DC signal which is used for recharging the rechargeable
battery 694 of the IPG, through a charge controller IC 682.
Additional circuitry within the IPG 391R includes, battery
protection IC 688 which controls a FET switch 690 to make sure that
the rechargeable battery 694 is charged at the proper rate, and is
not overcharged. The battery protection IC 688 can be an
off-the-shelf IC available from Motorola (part no. MC 33349N-3R1).
This IC monitors the voltage and current of the implanted
rechargeable battery 694 to ensure safe operation. If the battery
voltage rises above a safe maximum voltage, the battery protection
IC 688 opens charge enabling FET switches 690, and prevents further
charging. A fuse 692 acts as an additional safeguard, and
disconnects the battery 694 if the battery charging current exceeds
a safe level. As also shown in FIG. 21, charge completion detection
is achieved by a back-telemetry transmitter 684, which modulates
the secondary load by changing the full-wave rectifier into a
half-wave rectifier/voltage clamp. This modulation is in turn,
sensed by the charger as a change in the coil voltage due to the
change in the reflected impedance. When detected through a back
telemetry receiver 676, either an audible alarm is generated or a
LED is turned on.
[0113] A simplified block diagram of charge completion and
misalignment detection circuitry is shown in conjunction with FIG.
22. As shown, a switch regulator 686 operates as either a full-wave
rectifier circuit or a half-wave rectifier circuit as controlled by
a control signal (CS) generated by charging and protection
circuitry 698. The energy induced in implanted coil 48B (from
external coil 46B) passes through the switch rectifier 686 and
charging and protection circuitry 698 to the implanted rechargeable
battery 694. As the implanted battery 694 continues to be charged,
the charging and protection circuitry 698 continuously monitors the
charge current and battery voltage. When the charge current and
battery voltage reach a predetermined level, the charging and
protection circuitry 698 triggers a control signal. This control
signal causes the switch rectifier 686 to switch to half-wave
rectifier operation. When this change happens, the voltage sensed
by voltage detector 702 causes the alignment indicator 706 to be
activated. This indicator 706 may be an audible sound or a flashing
LED type of indicator.
[0114] The indicator 706 may similarly be used as a misalignment
indicator. In normal operation, when coils 46B (external) and 48B
(implanted) are properly aligned, the voltage V.sub.s sensed by
voltage detector 704 is at a minimum level because maximum energy
transfer is taking place. If and when the coils 46B and 48B become
misaligned, then less than a maximum energy transfer occurs, and
the voltage V.sub.s sensed by detection circuit 704 increases
significantly. If the voltage V.sub.s reaches a predetermined
level, alignment indicator 706 is activated via an audible speaker
and/or LEDs for visual feedback. After adjustment, when an optimum
energy transfer condition is established, causing V.sub.s to
decrease below the predetermined threshold level, the alignment
indicator 706 is turned off.
[0115] The elements of the external recharger are shown as a block
diagram in conjunction with FIG. 23. In this disclosure, the words
charger and recharger are used interchangeably. The charger base
station 680 receives its energy from a standard power outlet 714,
which is then converted to 5 volts DC by a AC-to-DC transformer
712. When the re-charger is placed in a charger base station 680,
the re-chargeable battery 672 of the re-charger is fully recharged
in a few hours and is able to recharge the battery 694 of the IPG
391R. If the battery 672 of the external re-charger falls below a
prescribed limit of 2.5 volt DC, the battery 672 is trickle charged
until the voltage is above the prescribed limit, and then at that
point resumes a normal charging process.
[0116] As also shown in FIG. 23, a battery protection circuit 718
monitors the voltage condition, and disconnects the battery 672
through one of the FET switches 716, 720 if a fault occurs until a
normal condition returns. A fuse 724 will disconnect the battery
672 should the charging or discharging current exceed a prescribed
amount.
[0117] It will be clear to one skilled in the art, that existing
systems such as disclosed in U.S. Pat. Nos. 6,615,084 and 5,423,872
both assigned to Cigaina can be adapted with technology disclosed
in this patent application, and both patents are incorporated
herein by reference.
[0118] Referring now to FIG. 24A, the implanted lead component of
the system is similar to cardiac pacemaker leads, except for distal
portion (or electrode end) of the lead. This figure shows a pair of
electrodes 61,62 that are used for providing electrical pulses for
stimulation. The lead terminal preferably is linear bipolar, even
though it can be bifurcated, and plug(s) into the cavity of the
pulse generator means. FIG. 24B shows an embodiment of a lead which
is tripolar, where one electrode can be used for blocking pulses,
and the other electrode pair can be used for stimulation pulses.
Blocking is described more fully in a co-pending application.
[0119] The lead body 59 insulation may be constructed of medical
grade silicone, silicone reinforced with polytetrafluoro-ethylene
(PTFE), or polyurethane. With reference to electrode materials, the
stimulating electrodes may be made of pure platinum,
platinum/Iridium alloy or platinum/iridium coated with titanium
nitride. The conductor connecting the terminal to the electrodes
61,62 is made of an alloy of nickel-cobalt. The implanted lead
design variables are also summarized in table two below.
2TABLE 2 Lead design variables Proximal Distal End End Conductor
(connecting Lead body- proximal Lead Insulation and distal
Electrode- Electrode- Terminal Materials Lead-Coating ends)
Material Type Linear Polyurethane Antimicrobial Alloy of Pure
Standard Ball bipolar coating Nickel- Platinum and Ring Cobalt
electrodes Bifurcated Silicone Anti- Platinum- Steroid Inflammatory
Iridium eluting coating (Pt/Ir) Alloy Silicone with Lubricious
Pt/Ir coated Polytetrafluoro- coating with Titanium ethylene
Nitride (PTFE) Carbon
[0120] Once the lead is fabricated, coating such as anti-microbial,
anti-inflammatory, or lubricious coating may be applied to the body
of the lead.
Telemetry Module
[0121] Shown in conjunction with FIG. 25, in one embodiment of the
invention the external pulse generator 42 and/or programmer 85 may
comprise two-way wireless communication capabilities with a remote
server, using a communication protocol such as the wireless
application protocol (WAP). The purpose of the telemetry module is
to enable the physician to remotely, via the wireless medium change
the programs, activate, or disengage programs. Additionally,
schedules of therapy programs, can be remotely transmitted and
verified. Advantageously, the physician is thus able to remotely
control the stimulation therapy.
[0122] FIG. 26 is a simplified schematic showing the communication
aspects between the stimulator 42 and/or programmer 85 and the
remote hand-held computer. Similar methodology would apply if the
telemetry module is in the programmer 85. A desktop or laptop
computer can be a server 130 which is situated remotely, perhaps at
a health-care provider's facility or a hospital. The data can be
viewed at this facility or reviewed remotely by medical personnel
on a wireless internet supported hand-held device 140, which could
be a personal data assistant (PDA), for example, a "palm-pilot"
from PALM corp. (Santa Clara, Calif.), a "Visor" from Handspring
Corp. (Mountain view, CA) or on a personal computer (PC) available
from numerous vendors or a cell phone or a handheld device being a
combination thereof. The physician or appropriate medical
personnel, is able to interrogate the external stimulator 42 device
and know what the device is currently programmed to, as well as,
get a graphical display of the pulse train. The wireless
communication with the remote server 130 and hand-held device
(wireless internet supported) 140 can be achieved in all
geographical locations within and outside the United States (US)
that provides cell phone voice and data communication service. The
pulse generation parameter data can also be viewed on the handheld
devices 140.
[0123] The telecommunications component of this invention uses
Wireless Application Protocol (WAP). WAP is a set of communication
protocols standardizing Internet access for wireless devices.
Previously, manufacturers used different technologies to get
Internet on hand-held devices. With WAP, devices and services
inter-operate. WAP promotes convergence of wireless data and the
Internet. The WAP Layers are Wireless Application Envirnment
(WAEW), Wireless Session Layer (WSL), Wireless Transport Layer
Security (WTLS) and Wireless Transport Layer (WTP).
[0124] The WAP programming model, which is heavily based on the
existing Internet programming model, is shown schematically in FIG.
27. Introducing a gateway function provides a mechanism for
optimizing and extending this model to match the characteristics of
the wireless environment. Over-the-air traffic is minimized by
binary encoding/decoding of Web pages and readapting the Internet
Protocol stack to accommodate the unique characteristics of a
wireless medium such as call drops. Such features are facilitated
with WAP.
[0125] The key components of the WAP technology, as shown in FIG.
27, includes 1) Wireless Mark-up Language (WML) 452 which
incorporates the concept of cards and decks, where a card is a
single unit of interaction with the user. A service constitutes a
number of cards collected in a deck. A card can be displayed on a
small screen. WML supported Web pages reside on traditional Web
servers. 2) WML Script which is a scripting language, enables
application modules or applets to be dynamically transmitted to the
client device and allows the user interaction with these applets.
3) Microbrowser, which is a lightweight application resident on the
wireless terminal that controls the user interface and interprets
the WML/WML Script content. 4) A lightweight protocol stack 454
which minimizes bandwidth requirements, guaranteeing that a broad
range of wireless networks can run WAP applications. The protocol
stack of WAP can comprise a set of protocols for the transport
(WTP), session (WSP), and security (WTLS) layers. WSP is binary
encoded and able to support header caching, thereby economizing on
bandwidth requirements. WSP also compensates for high latency by
allowing requests and responses to be handles asynchronously,
sending before receiving the response to an earlier request. For
lost data segments, perhaps due to fading or lack of coverage, WTP
only retransmits lost segments using selective retransmission,
thereby compensating for a less stable connection in wireless. The
above mentioned features are industry standards adopted for
wireless applications, and well known to those skilled in the
art.
[0126] The presently preferred embodiment utilizes WAP, because WAP
has the following advantages, 1) WAP protocol uses less than
one-half the number of packets that the standard HTTP or TCP/IP
Internet stack uses to deliver the same content. 2) Addressing the
limited resources of the terminal, the browser, and the lightweight
protocol stack are designed to make small claims on CPU and ROM. 3)
Binary encoding of WML and SML Script helps keep the RAM as small
as possible. And, 4) Keeping the bearer utilization low takes
account of the limited battery power of the terminal.
[0127] In this embodiment two modes of communication are possible.
In the first, the server initiates an upload of the actual
parameters being applied to the patient, receives these from the
stimulator, and stores these in its memory, accessible to the
authorized user as a dedicated content driven web page. The web
page is managed with adequate security and password protection. The
physician or authorized user can make alterations to the actual
parameters, as available on the server, and then initiate a
communication session with the stimulator device to download these
parameters.
[0128] The physician is also able to set up long-term schedules of
stimulation therapy for their patient population, through wireless
communication with the server. The server in turn communicates
these programs to the neurostimulator. Each schedule is securely
maintained on the server, and is editable by the physician and can
get uploaded to the patient's stimulator device at a scheduled
time. Thus, therapy can be customized for each individual patient.
Each device issued to a patient has a unique identification key in
order to guarantee secure communication between the wireless server
130 and stimulator device 42 (or programmer 85).
[0129] Shown in conjunction with FIG. 28, in one embodiment, the
external stimulator 42 and/or the programmer 85 may also be
networked to a central collaboration computer 286 as well as other
devices such as a remote computer 294, PDA 140, phone 141,
physician computer 143. The interface unit 292 in this embodiment
communicates with the central collaborative network 290 via
land-lines such as cable modem or wirelessly via the internet. A
central computer 286 which has sufficient computing power and
storage capability to collect and process large amounts of data,
contains information regarding device history and serial number,
and is in communication with the network 290. Communication over
collaboration network 290 may be effected by way of a TCP/IP
connection, particularly one using the internet, as well as a PSTN,
DSL, cable modem, LAN, WAN or a direct dial-up connection.
[0130] The standard components of interface unit shown in block 292
are processor 305, storage 310, memory 308, transmitter/receiver
306, and a communication device such as network interface card or
modem 312. In the preferred embodiment these components are
embedded in the external stimulator 42 and can also be embedded in
the programmer 85. These can be connected to the network 290
through appropriate security measures (Firewall) 293.
[0131] Another type of remote unit that may be accessed via central
collaborative network 290 is remote computer 294. This remote
computer 294 may be used by an appropriate attending physician to
instruct or interact with interface unit 292, for example,
instructing interface unit 292 to send instruction downloaded from
central computer 286 to remote implanted unit.
[0132] Shown in conjunction with FIGS. 29A and 29B the physician's
remote communication's module is a Modified PDA/Phone 140 in this
embodiment. The Modified PDA/Phone 140 is a microprocessor based
device as shown in a simplified block diagram in FIGS. 65A and 65B.
The PDA/Phone 140 is configured to accept PCM/CIA cards specially
configured to fulfill the role of communication module 292 of the
present invention. The Modified PDA/Phone 140 may operate under any
of the useful software including Microsoft Window's based, Linux,
Palm OS, Java OS, SYMBIAN, or the like.
[0133] The telemetry module 362 comprises an RF telemetry antenna
142 coupled to a telemetry transceiver and antenna driver circuit
board which includes a telemetry transmitter and telemetry
receiver. The telemetry transmitter and receiver are coupled to
control circuitry and registers, operated under the control of
microprocessor 364. Similarly, within stimulator a telemetry
antenna 142 is coupled to a telemetry transceiver comprising RF
telemetry transmitter and receiver circuit. This circuit is coupled
to control circuitry and registers operated under the control of
microcomputer circuit.
[0134] With reference to the telecommunications aspects of the
invention, the communication and data exchange between Modified
PDA/Phone 140 and external stimulator 42 operates on commercially
available frequency bands. The 2.4-to-2.4853 GHz bands or 5.15 and
5.825 GHz, are the two unlicensed areas of the spectrum, and set
aside for industrial, scientific, and medical (ISM) uses. Most of
the technology today including this invention, use either the 2.4
or 5 GHz radio bands and spread-spectrum technology.
[0135] The telecommunications technology, especially the wireless
internet technology, which this invention utilizes in one
embodiment, is constantly improving and evolving at a rapid pace,
due to advances in RF and chip technology as well as software
development. Therefore, one of the intents of this invention is to
utilize "state of the art" technology available for data
communication between Modified PDA/Phone 140 and external
stimulator 42. The intent of this invention is to use 3G technology
for wireless communication and data exchange, even though in some
cases 2.5G is being used currently.
[0136] For the system of the current invention, the use of any of
the "3G" technologies for communication for the Modified PDA/Phone
140, is considered within the scope of the invention. Further, it
will be evident to one of ordinary skill in the art that as future
4G systems, which will include new technologies such as improved
modulation and smart antennas, can be easily incorporated into the
system and method of current invention, and are also considered
within the scope of the invention.
* * * * *