Ex Parte Behnke

Patent Trial and Appeal Board

Jun 23, 2017

11328766 (P.T.A.B. Jun. 23, 2017)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
11/328,766 01/10/2006 Robert Behnke H-US-00259 (203-3889) 4779
90039 7590
Covidien LP
Attn: IP Legal
5920 Longbow Drive
Mail Stop A36
Boulder, CO 80301-3299
06/27/2017 EXAMINER
GOOD, SAMANTHA M
ART UNIT PAPER NUMBER
3739
NOTIFICATION DATE DELIVERY MODE
06/27/2017 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
mail @ cdfslaw. com
SurgicalUS@covidien.com
medtronic_mitg-si_docketing@cardinal-ip.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte ROBERT BEHNKE1
Appeal 2016-005737
Application 11/328,766
Technology Center 3700
Before JEFFREY N. FREDMAN, TAWEN CHANG, and
DEVON ZASTROW NEWMAN, Administrative Patent Judges.
CHANG, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134(a) involving claims to system
and method for controlling an electrosurgical generator using a full bridge
topology, which have been rejected as obvious. We have jurisdiction under
35 U.S.C. § 6(b).
We AFFIRM.
STATEMENT OF THE CASE
“An electrosurgical generator is used in surgical procedures to deliver
electrical energy to the tissue of a patient.” (Spec. 1.) An electrode
1 Appellant identifies the Real Party in Interest as Covidien LP. (Appeal Br.
1.)
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Application 11/328,766
connected to the generator “can be used for cutting, coagulating or sealing
the tissue of a patient with high frequency electrical energy.” (Id.) Different
waveforms of electrical energy enhance the energy’s ability to engage in
different modes of operation (e.g., cutting or coagulating the tissue). (Id. at
2.) “In each mode of operation, it is important to regulate the electrosurgical
power delivered to the patient to achieve the desired surgical effect.” (Id.)
Likewise, more or less power may be necessary depending on the type or
condition (e.g., desiccation) of the tissue encountered during the surgical
procedure. (Id. at 2—3.) It is therefore desirable that “the response time of
the electrosurgical control of output power ... be rapid enough to
seamlessly permit the surgeon to treat the tissue.” (Id. at 2.)
According to the Specification, the invention relates to “[a]n
electrosurgical generator that uses a full bridge topology as the [radio
frequency] RF output stage to control the output RF energy.” (Id. at 4.) The
Specification states that using a full bridge topology and controlling the RF
energy directly at the RF output stage rather than through varying direct
current (DC) input allow the electrosurgical generator to, among other
things, respond faster and to provide a stable output. (Id. at 5.) Further
according to the Specification, “[s]ince[] the RF output stage . . . responds to
a dynamic load [e.g., tissue] ten times faster than the microprocessor,. . .
over-voltage and over-current conditions may occur at the load,” and the
invention includes “hardware solutions ... to help minimize these
conditions.” (Id. at 9, 10.)
Claims 1—5, 7—13, and 15—18 are on appeal. Claim 1 is illustrative
and reproduced below:
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Application 11/328,766
1. A system for controlling an electrosurgical
generator using a full bridge topology, comprising:
a high voltage direct current power source which supplies
power;
a radio frequency output stage which receives power from
the high voltage direct current power source and outputs radio
frequency energy at a predetermined radio frequency set point;
at least one sensor which determines at least one parameter
of the radio frequency energy being applied to a load;
a microprocessor configured to receive the at least one
parameter of the radio frequency energy and output the
predetermined radio frequency set point to the radio frequency
output stage as a function of the at least one parameter of the
radio frequency energy, the predetermined radio frequency set
point is disproportional to the outputted radio frequency energy;
and
an over-current protection circuit including a first current
sense transformer and a first comparator, the first current sense
transformer configured to measure output current to the load, and
the first comparator configured to compare the output current to
a reference voltage, wherein if the output current is greater than
the reference voltage, the microprocessor is configured to set the
radio frequency set point to 0V for a predetermined period of
time.
(Appeal Br. 4 (Claims App’x).)
The Examiner rejects claims 1—5, 7—13, and 15—18 under 35 U.S.C.
§ 103(a) as being unpatentable over Thompson,2 Gentelia,3 and Eggers.4
(Final Act. 2.)
2 Thompson, US 2004/0095100 Al, published May 20, 2004.
3 Gentelia et al., U.S. Patent No. 5,599,348, issued Feb. 4, 1997.
4 Eggers et al., U.S. Patent No. 6,740,079 Bl, issued May 25, 2004.
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Application 11/328,766
DISCUSSION
Issue
The Examiner finds that Thompson teaches each element of claim 1,
except that it does not expressly teach a first comparator that compares the
output current to a reference voltage and the microprocessor setting the
predetermined radio frequency set point to 0V based on the result of such
comparison. (Final Act. 2—5.)
The Examiner finds that Gentelia teaches a system for controlling an
electrosurgical generator comprising a “circuit (68) including a first current
sense transformer (72) that measures output current to the load and a first
comparator (76) configured to compare the output current to a reference
voltage,” wherein the microprocessor “sets the predetermined radio
frequency set point to 0V for a predetermined period of time” based on the
outcome of the comparison. (Id. at 4—5 (citations omitted).) The Examiner
similarly finds that Eggers teaches “a[] . . . system for controlling an
electrosurgical generator comprising an over-current protection circuit
(Figure 35) comprising a comparator configured to compare the output
current to a reference voltage to establish wherein if the output current is
greater than the reference voltage.” (Id. at 5.)
The Examiner concludes that it would have been obvious for a skilled
artisan to modify Thompson’s system for controlling an electrosurgical
generator with Gentelia’s circuit having a comparator that compares output
current to a reference voltage such that the microprocessor sets
predetermined radio frequency set point to 0V for a predetermined period of
time, in order to “provide a safer operating condition ... by indicating a
predetermined time period before electrosurgery can be resumed.” (Final
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Application 11/328,766
Act. 5.) The Examiner also concludes that it would have been obvious to a
skilled artisan to further modify the comparator discussed above by
configuring it to compare the output current to a reference voltage to
establish whether the output current is greater than the reference voltage, as
taught by Eggers, “in order to monitor for a high voltage over-current
condition.” (Id. at 5—6.)
Appellant contends that there is no suggestion or motivation to modify
Thompson with Gentelia and Eggers because combining the teachings of
Thompson, Gentelia, and Eggers would result in a system “inoperable for its
intended purpose and/or change the principle of operation of the prior art
being modified.” (Br. 4.)
The issue with respect to this rejection is whether the Examiner’s
proposed combination of Thompson, Gentelia, and Eggers would result in a
system inoperable for its intended purpose and/or change the prior art’s
principle of operation.
Findings of Fact
1. Gentelia teaches a trocar device incorporating “an
electrosurgical cutting element which . . . provides cutting of tissue through
the transmission of radio frequency electrical energy to the area to be cut.”
(Gentelia 1:47—52.)
2. Gentelia teaches that the electrosurgical cutting element is used
to “make a guide hole for the cannula and thus enables the remainder of the
trocar assembly to enlarge the puncture.” (Id. at Abstract.)
3. Gentelia teaches that the electrosurgical cutting element is,
in use, connected to a conventional electrosurgical generator or
other source of radio frequency (r.f.) power or energy (the term
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Appeal 2016-005737
Application 11/328,766
electrosurgical generator being used herein to refer to any
suitable source for driving the electrosurgical cutting element),
and a further important feature of the trocar assembly of the
invention is in the provision of an electronic control circuit for
sensing current flow and, when the trocar breaks the wall of the
organ involved, for opening or cutting off the connection to the
electrosurgical generator. This feature substantially eliminates
any chance of an unintended puncture.
In addition, further circuitry is preferably provided which
requires that the operator (surgeon) release a control switch for
a predetermined time period prior to resuming surgical
operations so that power is again provided to the electrosurgical
cutting element only as the result of a conscious decision on the
part of the operator. As a result, inadvertent operation of the
cutting element, and thus possible inadvertent puncturing of the
organ wall, are combatted or avoided.
(Mat 1:63-2:14.)
4. Figure 8 of Gentelia is reproduced below:
+v sw
(Id. at Fig. 8.) Figure 8 depicts “a schematic circuit diagram of the cutoff
circuit.” (Id. at 2:54—55.) Referring to Figure 8, Gentelia teaches that
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Application 11/328,766
[t]he cutoff circuit 68 . . . includes a current transformer 72
connected to the generator output line ... so as to sense or
monitor the current flow from the electrosurgical generator . . .
to the trocar assembly 10. The . . . transformer 72 is connected
to a rectifier 74 which produces an output voltage that is a
function of the current level. Rectifier 74 is connected to an
adjustable voltage comparator 76 which determines the cutoff
current by comparing the output voltage produced by rectifier
74 with a predetermined reference level. The output of
comparator 76 is connected to one input of an OR gate 78 the
output of which is connected to an AND gate 80.........
A control switch 82 is provided for controlling
energizing of the electrosurgical generator. This switch ... is
controlled by the surgeon. A pair of delay networks, a start
delay circuit 84 and a reset delay counter circuit 86, are
connected to switch 82 in parallel with each other. Start delay
circuit 84 begins timing out its associated delay when switch 82
is closed while reset delay counter circuit 86 begins timing out
its associated delay when switch 82 is opened.........
The output of start delay circuit 84 is connected to the
other input of OR gate 78 and the delay provided allows time
for the surgeon to start a cut after activating the switch 82.
Thus, when switch 82 is closed the output of start delay circuit
78 provides for closing of a control relay 88 for the
electrosurgical generator so as to turn on the electrosurgical
generator......... After delay circuit 84 times out, the operation
of relay 88 is controlled by the output of the current sensor 72
and, more particularly, by the output of comparator 76. Thus, if
this output drops below the level set within comparator 76,
relay 88 is opened and power to the electrosurgical generator is
cut off.
{Id. at 4:56-5:35.)
5. Eggers teaches “[a]n electrosurgical generator which provides a
constant voltage and variable power output particularly suited for cutting arc
formation at an active electrode which exhibits a dynamic active surface area
of varying geometry.” (Eggers Abstract.)
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6. Figure 35 of Eggers is reproduced below:
FTa35
(Id. at Figure 35.) Figure 35 depicts “an electrical schematic diagram of a
circuit monitoring an output over-current condition.” (Id. at 5:5—6.)
Referring to Figure 35, Eggers teaches that
the current signals HV_I+ and HV_I- as were developed at the
high voltage output stage 450 ... are rectified. In this regard
positive current is introduced [to] intermediate diode pair D84
and D85 from line 796 and negative current signals are
introduced to diode pair D86 and D87 from line 820. These
rectifying diode pairs are located between lines 1130 and 1132,
the latter being coupled with secondary ground and the former
providing the earlier-described output current signal, IOUT as
represented at line 1134. . . . Line 1130 extends to one input of
a comparator 1136 having output at line 1138 extending
through pull-up resistor R178 to +12V and coupled to the gate
of transistor Q20 from line 1140. Comparator 1136 is
configured for establishing a high voltage over-current
threshold reference input at line 1142 in conjunction with +12V
source and resistors R179—R181. With the arrangement shown,
a low true output at the comparator 1136 generates a
corresponding over-current signal, “HV_OC” at line 1144 by
turning off transistor Q20.
(Id. at 38:57-39:13.)
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Analysis
We agree with the Examiner that the Examiner’s combination of
Thompson, Gentelia, and Eggers would not result in an inoperable system.
Appellant argues that Gentelia teaches a comparator “wherein the
electrosurgical general is cut off if the output voltage produced by the
rectifier 74 drops below the predetermined reference level.” (Br. 5.)
Appellant argues that
[f]urther modifying the modified Thomson system (as modified
by Gentelia) to require that the modified comparator cut off
power to the electrosurgical generator when the output is
greater than the level set within the comparator (as allegedly
taught by Eggers), would render the modified Thompson
reference inoperable for its intended purpose and change the
principle of operation of the prior art being modified.
Specifically, further modifying the modified Thompson
reference to include the alleged teachings of Eggers, would
result in power being cut off both: 1) when the output is below
the reference voltage; and 2) when the output is greater than the
reference voltage. That is, further modifying the modified
Thomson system would result in a generator where power is
always cut off.
(Br. 5.)
We are not persuaded. As the Examiner points out,
[t]he test for obviousness is not whether the features of a
secondary reference may be bodily incorporated into the
structure of the primary reference; nor is it that the claimed
invention must be expressly suggested in any one or all of the
references. Rather, the test is what the combined teachings of
the references would have suggested to those of ordinary skill
in the art.
(Ans. 2 (quoting in re Keller, 642 F,2d 413, 425 (CCPA 1981).) In this
case, Gentelia teaches a circuit comprising a comparator that cuts off the
power to the electrosurgical generator when the trocar breaks the wall of the
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Application 11/328,766
organ (indicated by the sensed current dropping below a reference level as
determined by the comparator), in order to avoid inadvertent puncturing of
the organ wall. (FF3, FF4.) Eggers teaches monitoring for an output over­
current condition when using an electro surgical generator and generating an
over-current signal when a comparator determines that the output current
exceeds a reference level. (FF6.) We agree with the Examiner that, in light
of the disclosures in Gentelia and Eggers, a skilled artisan attempting to
minimize the problem of an output over-current condition in Thompson’s
electrosurgical generator would have reason to incorporate Gentelia’s circuit
wherein the comparator is modified, pursuant to Eggers’ disclosure, so as to
generate a signal when the current exceeds, rather than falls below, the
reference level. (Ans. 2—3.)
For the reasons above, we affirm the Examiner’s rejection of claim 1.
Claims 2—5, 7—13, and 15—18, which are not separately argued, fall with
claim 1. 37 C.F.R. § 41.37(c)(l)(iv).
TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED
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