Exhibit 10.44

Portions of this document have been redacted pursuant to a Request
for Confidential Treatment filed with the Securities and Exchange Commission.
Redacted portions are indicated with the notation "*****"


                      STOCK PURCHASE AND VESTING AGREEMENT



               THIS STOCK PURCHASE AND VESTING AGREEMENT is made this 21st day
of March, 2002, by and between Spine Wave, Inc., a Delaware corporation (the
"Company"), and Protein Polymer Technologies, Inc., a Delaware corporation
("Purchaser").

               NOW THEREFORE, IT IS HEREBY AGREED:

               1. Sale of Stock. Subject to the terms hereof, the Company shall
sell to Purchaser and Purchaser shall purchase from the Company Four Hundred
Thousand (400,000) shares of common stock of the Company (the "Stock"). The sale
and purchase shall occur at the offices of the Company on the date set forth
above or at such other place and time as the parties may agree (the "Closing").

               2. Consideration. In exchange for and as full consideration for
the Stock, the Purchaser shall (i) enter into that certain Amendment No. 1 to
the Supply and Services Agreement dated April 12, 2001 attached hereto as
Exhibit A (the "Amendment"), (ii) have entered into and delivered to the Company
that certain Certificate of Acknowledgement of Termination by and among the
Company, Purchaser and Windamere Venture Partners, LLC terminating that certain
Voting Agreement dated April 12, 2001, attached hereto as Exhibit B (the
"Certificate of Termination"), (iii) have entered into and delivered to the
Company that certain Letter Agreement attached hereto as Exhibit C (the "Letter
Agreement") and (iv) have previously voted all of the shares of the Company's
capital stock beneficially held by Purchaser in favor of (A) the Company's
merger with VERTx, Inc. (the "Merger") and (B) the Company's sale and issuance
of shares of the Company's Series A Preferred Stock (the "Series A Financing")
to certain investors immediately thereafter and (C) any matter that could
reasonably be expected to facilitate the Merger and Series A Financing as well
as delivered to the Company or its representatives written evidence thereof. In
addition, Purchaser shall deliver two (2) duly executed blank Assignments
Separate from Certificate in the form attached hereto as Exhibit D, which
Assignments Separate from Certificate shall only be used in connection with the
exercise of the Company's Repurchase Option as set forth in Section 5 below. The
Company and the Purchaser agree that the fair market value of each share of
Stock as of the date of this Agreement equals $0.05 per share (the "Purchase
Price").

               3. Issuance of Stock. Upon the execution and delivery of the
Amendment, Certificate of Termination and Letter Agreement by the Purchaser and
contingent upon the Company's verification of Purchaser's vote in favor of the
approval of the Merger and the Series A Financing, the Company shall issue a
duly executed certificate evidencing the Stock in the name of Purchaser and
provide Purchaser with a copy of such certificate. The original of such
certificate shall be held in escrow by the Company until the expiration of the
Repurchase Option (as defined below); provided however, upon Purchaser's
request, Company shall release to Purchaser a certificate representing that
number of shares of the Stock which, as of the date of such request, are no
longer subject to the Repurchase Option.

               4. Repurchase Option. The Stock shall be subject to a right (but
not an obligation) of repurchase by the Company (the "Repurchase Option"). The
Company shall have the



<PAGE>



right to purchase Unvested Shares (as defined below) from the Purchaser at the
Purchase Price as follows.

                      a. All of the Stock shall initially be considered
"Unvested Shares" subject to the Repurchase Option.

                      b. The Repurchase Option shall lapse with respect to such
portion of the Stock upon the attainment by Purchaser of each of the performance
milestones as set forth on Exhibit E attached hereto (the "Milestones").

                      c. The Repurchase Option shall also terminate and cease to
be exercisable with respect to any and all Unvested Shares in the event of (i)
the consummation of a merger or consolidation of the Company ("Merger") with and
into another corporation where the Company's stockholders of record immediately
prior to such merger or consolidation hold less than fifty percent (50%) of the
outstanding voting stock of the successor corporation, (ii) a sale or transfer
of greater than fifty percent (50%) of the outstanding voting stock of the
Company (other than as a result of a transaction or series of transactions the
primary purpose of which is the raising of equity capital) (a "Sale") or (iii)
the completion of a sale of all or substantially all of the Company's assets.

                      d. The Repurchase Option shall be exercised by written
notice signed by the President or Treasurer of the Company and delivered as
provided in subparagraph 9(b) hereof. The Company shall pay for the shares of
Stock it has elected to repurchase by delivery of a cashier's check or by wire
transfer of immediately available funds in an aggregate amount equal to the
Purchase Price multiplied by the number of shares of Stock being repurchased.


                      e. Adjustments to Stock. If, from time to time during the
term of the Repurchase Option, there is any change affecting the Company's
outstanding common stock as a class that is effected without the receipt of
consideration by the Company (through merger, consolidation, reorganization,
reincorporation, stock dividend, dividend in property other than cash, stock
split, liquidating, dividend, combination of shares, change in corporation
structure or other transaction not involving the receipt of consideration by the
Company), then any and all new, substituted or additional securities or other
property to which Purchaser is entitled by reason of Purchaser's ownership of
Stock shall be immediately subject to the Repurchase Option and be included in
the word "Stock" for all purposes of the Repurchase Option with the same force
and effect as the shares of the Stock presently subject to the Repurchase
Option, but only to the extent the Stock is, at the time, covered by such
Repurchase Option. While the aggregate Purchase Price shall remain the same
after each such event, the Purchase Price per share of Stock upon exercise of
the Repurchase Option shall be appropriately adjusted.

               5. Exercise of Repurchase Option. The Company shall have the
right to exercise its Repurchase Option as follows:

                      a. The Company shall have the right to exercise its
Repurchase Option to repurchase any Unvested Shares covered by the First
Milestone and the Second



                                       2
<PAGE>



Milestone (each as defined and set forth on Exhibit E) from Purchaser at the
Purchase Price at any time on or after*****

                      b. The Company shall have the right to exercise its
Repurchase Option to repurchase any Unvested Shares covered by the Third
Milestone (as defined and set forth on Exhibit E) from Purchaser at the Purchase
Price at any time on or after*****

               6. Right of First Refusal. Stock subject to the Repurchase Option
may not be transferred, except for transfers by operation of law or other
involuntary transfer. Before any shares of Stock registered in the name of
Purchaser, not subject to the Repurchase Option and not otherwise restricted by
applicable federal and state securities laws may be sold or transferred
(excluding transfer by operation of law or other involuntary transfer) such
shares shall first be offered to the Company in the following manner:

                      a. The Purchaser or its transferee shall deliver a notice
pursuant to subparagraph 10(b) ("Notice") to the principal business office of
the Company stating (i) the bona fide intention to sell or transfer such shares,
(ii) the number of such shares of Stock to be sold or transferred, (iii) the
price and other terms, if any, for which Purchaser or its transferee proposes to
sell or transfer such shares of Stock, and (iv) the name and address of the
proposed purchaser or transferee, if any, and that such identified purchaser or
transferee is committed to acquire the stated number of shares on the stated
price and terms.

                      b. The Company shall have the right at any time within ten
(10) days of receipt of the Notice to purchase all of the shares to which the
Notice refers at the price per share specified in the Notice. Said right shall
be exercised by written notice signed by the President or any Vice President of
the Company and delivered as provided in subparagraph 10(b) hereof, which notice
shall specify the time, place and date for settlement of such purchase.

                      c. In the event the Company does not, for any reason,
exercise its right pursuant hereto, the Company may assign such right, provided
such right shall not extend beyond such ten (10) day period. If exercised by the
assignee pursuant hereto, the right to purchase shall be exercised by written
notice signed by the exercising assignee and delivered as provided in
subparagraph 10(b) hereof, which notice shall specify the time, place and date
for settlement of such purchase. Purchaser shall sell the shares to the Company
or such assignees within thirty (30) days after the date of the Notice.

                      d. If all of the shares to which the Notice refers are not
purchased, as provided in subparagraphs 6(b) or 6(c) above, the Purchaser may
sell such shares to the person named in the Notice at the price and terms
specified in the Notice, provided that such sale or transfer is consummated
within seventy five (75) days of the date of the Notice to the Company, and
provided further that any such sale is in accordance with all the terms and
conditions hereof. If Purchaser does not consummate the sale or transfer within
such seventy five (75) day period, the right provided hereby shall be deemed to
be revived with respect to such shares and no sale or transfer shall be effected
without first offering the shares in accordance herewith.


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


                                       3
<PAGE>



                      e. Notwithstanding the above, neither the Company nor the
assignees of the Company shall have any right of first refusal under this
Section 6 at any time subsequent to the following: (i) the closing of a bona
fide, firm commitment underwritten public offering of the common stock of the
Company pursuant to a Registration Statement declared effective under the Act,
(ii) the first date on which the Stock is held of record by more than five
hundred (500) persons (ii) a Merger or Sale, other than a Merger or Sale in
which the consideration includes capital stock that is not registered under the
Securities Act of 1933, as amended, and/or is not listed on a national
securities exchange, unless the issuer is subject to a contractual obligation to
register and list such stock within six months of such Merger or Sale. In
addition, the Company's right of first refusal under this Section 6 shall not
apply to the proposed sale or transfer by Purchaser of stock subject to this
Agreement as part of the sale of all or substantially all of Purchaser's assets
("Sale of Assets") except in the event that the Sale of Assets is to a direct
competitor of the Company or to such other entity which directly or indirectly
controls a direct competitor of the Company and provided that in such
circumstance, the time period set forth in subparagraph 6(d) above shall be 180
days.

               7. "Market Stand-Off" Agreement. If requested by the Company and
an underwriter of Common Stock (or other securities) of the Company, Purchaser
shall not sell or otherwise transfer or dispose of any Common Stock (or other
securities) of the Company held by such Holder (other than those included in the
registration) for no more than (i) 180 days from the effective date of the first
registration of the Company's securities, including securities to be sold on its
behalf to the public in an underwritten offering and (ii) 90 days for the next
two subsequent registration statement of the Company after the initial public
offering; provided, however, that all executive officers, directors and two
percent (2%) or greater stockholders of the Company must enter into similar
lock-up agreements as well.

               In order to enforce the foregoing covenant, the Company may
impose stop-transfer instructions with respect to common stock held by Purchaser
until the end of such period.

               8. Representations and Warranties of Purchaser.

                      a. Due Authorization. Purchaser hereby represents and
warrants to Company that it is duly authorized and empowered to enter into and
perform this Agreement; and the execution and performance of this Agreement by
Purchaser does not and will not conflict with or violate any contract,
agreement, indenture, mortgage, instrument, writ, judgment, or order of any
court, arbiter or governmental or quasi-governmental body to which Purchaser is
a party or by which Purchaser is bound.

                      b. Investment Intent. This Agreement is made with
Purchaser in reliance upon its representation to the Company, which by
Purchaser's acceptance hereof confirms, that the Stock has been acquired by
Purchaser for investment for an indefinite period for Purchaser's own account,
not as a nominee or agent, and not with a view to the sale or distribution of
any part thereof, and that Purchaser has no present intention of selling,
granting participation in, or otherwise distributing the same. By executing this
Agreement, Purchaser further represents that Purchaser does not have any
contract, undertaking, agreement or arrangement with any person to sell,
transfer, or grant participations, to such person or to any third person, with
respect to any of the Stock.



                                       4
<PAGE>


                      c. Restricted Securities. Purchaser understands that the
Stock has not been registered under the Act, on the ground that the sale
provided for in this Agreement is exempt from the registration requirements of
the Act, and that the Company's reliance on such exemption is predicated on
Purchaser's representations set forth herein.

               Purchaser understands that if the Company does not register with
the Securities and Exchange Commission pursuant to Section 12 or 15 of the
Securities Exchange Act of 1934, as amended, or if a registration statement
covering the Stock (or a filing pursuant to the exemption from registration
under Regulation A of the Act) under the Act is not in effect when Purchaser
desires to sell the Stock, Purchaser may be required to hold the Stock for an
indeterminate period. The Purchaser also acknowledges that Purchaser understands
that any sale of the Stock that might be made by Purchaser in reliance upon Rule
144 under the Act may be made only in limited amounts in accordance with the
terms and conditions of that rule and that Purchaser may not be able to sell the
Stock at the time or in the amount Purchaser so desires. Purchaser is familiar
with Rule 144 and understands that the Stock constitutes "restricted securities"
within the meaning of that Rule.

                      d. Investment Experience. In connection with the
investment representations made herein Purchaser represents that Purchaser is
either an "Accredited Investor", as that term is defined in Rule 501 of
Regulation D promulgated under the Act, or is able to fend for itself in the
transactions contemplated by this Agreement, has such knowledge and experience
in financial and business matters as to be capable of evaluating the merits and
risks of its investment, has the ability to bear the economic risks of its
investment and has been furnished with and has had access to such information as
Purchaser has requested and deems appropriate to its investment decision.

                      e. Limitations on Disposition. Purchaser agrees that in no
event will Purchaser make a disposition of any of the Stock, unless and until
(i) Purchaser shall have notified the Company of the proposed disposition, and
(ii) Purchaser shall have furnished the Company with an opinion of counsel
satisfactory to the Company to the effect that such disposition will not require
registration of such Stock under the Act or that appropriate action necessary
for compliance with the Act has been taken, or (iii) the Company shall have
waived, expressly and in writing, its rights under clauses (i) and (ii) of this
subparagraph. In addition, prior to any disposition of any of the Stock, the
Company shall require the transferee or assignee to provide in writing
investment representations and such transferee's or assignee's agreement to be
bound by the market stand-off provisions hereof in a form acceptable to the
Company.

                      The Company shall not be required (i) to transfer on its
books any shares of Stock of the Company which shall have been sold or
transferred in violation of any of the provisions set forth in this Agreement,
or (ii) to treat as owner of such shares or to accord the right to vote as such
owner or to pay dividends to any transferee to whom such shares shall have been
so transferred. Purchaser shall, during the term of this Agreement, exercise all
rights and privileges of a stockholder of the Company with respect to the Stock
after the issuance, and prior to the repurchase, thereof.



                                       5
<PAGE>



                      f. Legends. All certificates representing any shares of
Stock of the Company subject to the provisions of this Agreement shall have
endorsed thereon the following legends:

                      (i) "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE
NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT").
THESE SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO
DISTRIBUTION OR RESALE, AND THEY MAY NOT BE TRANSFERRED WITHOUT AN EFFECTIVE
REGISTRATION STATEMENT FOR SUCH SHARES UNDER THE ACT OR PURSUANT TO RULE 144
UNDER THE ACT OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT
REGISTRATION IS NOT REQUIRED UNDER THE ACT."

                      (ii) "THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE
SUBJECT TO THE TERMS AND CONDITIONS OF A CERTAIN STOCK PURCHASE AND VESTING
AGREEMENT BETWEEN THE COMPANY AND THE HOLDER HEREOF WHICH INCLUDES A MARKET
STAND-OFF AGREEMENT, A RIGHT OF REPURCHASE AND A RIGHT OF FIRST REFUSAL ON THE
SALE OF THE SECURITIES. THESE SECURITIES MAY NOT BE SOLD, ASSIGNED, TRANSFERRED,
ENCUMBERED, OR IN ANY MANNER DISPOSED OF EXCEPT IN CONFORMITY WITH THE TERMS OF
SUCH AGREEMENT. COPIES OF THE AGREEMENT MAY BE OBTAINED UPON WRITTEN REQUEST TO
THE SECRETARY OF THE COMPANY."

                      (iii) Any legend required to be placed thereon by
applicable state laws.

               9. Representations and Warranties of Company.

                      a. Company hereby represents and warrants to Purchaser
that it is duly authorized and empowered to enter into and perform this
Agreement; and the execution and performance of this Agreement by the Company
does not and will not conflict with or violate any contract, agreement,
indenture, mortgage, instrument, writ, judgment, or order of any court, arbiter
or governmental or quasi governmental body to which the Company is a party or by
which the Company is bound.

                      b. To the best of its knowledge, all business and
financial information that the Company has provided to Purchaser is accurate in
all material respects; provided, however, that Purchaser acknowledges that the
business and financial information provided by the Company to Purchaser includes
certain statements and estimates provided by the Company and its representatives
with respect to the historical, pro forma and anticipated performance of the
Company or that of potential strategic partners. Such statements and estimates
reflect various assumptions by the Company, which may or may not prove to be
accurate, as well as the exercise of a substantial degree of judgement by the
Company as to the scope and presentation of such information.

               10. Miscellaneous.



                                       6
<PAGE>



                      a. Further Instruments and Actions. The parties agree to
execute such further instruments and to take such further action as may
reasonably be necessary to carry out the intent of this Agreement.

                      b. Notices. All notices required or permitted hereunder
shall be in writing and shall be deemed effectively given: (i) upon personal
delivery to the party to be notified, (ii) when sent by confirmed facsimile
transmission if sent during normal business hours of the recipient; if not, then
on the next business day, or (iii) for domestic addresses one (1) business day
after deposit with a nationally recognized overnight courier, specifying next
day delivery, with written verification of receipt and for international
addresses three (3) business days after deposit with a nationally recognized
overnight courier, specifying next day delivery, with written verification of
receipt. All communications shall be sent to the party to be notified at the
address as set forth on the signature pages hereof or at such other address as
such party may designate by ten (10) days advance written notice to the other
parties hereto.

                      c. Governing Law, Assignment and Enforcement. This
Agreement is governed by the internal law of California and shall inure to the
benefit of the successors and assigns of the Company and, subject to the
restrictions on transfer herein set forth, be binding upon Purchaser, its
successors and assigns. The prevailing party in any action to enforce this
Agreement shall be entitled to attorneys' fees and costs. The parties agree that
damages are not an adequate remedy for breach hereof and each party shall
accordingly be entitled to specific performance of this Agreement.

                      d. Entire Agreement; Amendments and Waivers. This
Agreement and the related Amendment, Certificate of Termination and Letter
Agreement, among Purchaser and Company, and all of even date herewith (and any
agreements, exhibits or schedules referenced therein), constitute the entire
agreement and understanding between the parties with respect to the subject
matter contained herein, and there are no promises, representations, conditions,
provisions or terms related thereto other than as set forth in this Agreement
and the related Amendment, Certificate of Termination and Letter Agreement
between the Purchaser and Company all of even date herewith. This Agreement may
only be amended with the written consent of the parties hereto, or their
successors or assigns, and no oral waiver or amendment shall be effective under
any circumstances whatsoever.

                      e. Cooperation. Purchaser agrees to cooperate
affirmatively with the Company, to the extent reasonably requested by the
Company, to enforce rights and obligations pursuant to this Agreement.

               11. California Commissioner of Corporations. THE SALE OF THE
SECURITIES WHICH ARE THE SUBJECT OF THIS AGREEMENT HAS NOT BEEN QUALIFIED WITH
THE COMMISSIONER OF CORPORATIONS OF THE STATE OF CALIFORNIA, AND THE ISSUANCE OF
SUCH SECURITIES OR THE PAYMENT OR RECEIPT OF ANY PART OF THE CONSIDERATION
THEREFOR PRIOR TO SUCH QUALIFICATION IS UNLAWFUL UNLESS THE SALE OF SECURITIES
IS EXEMPT FROM QUALIFICATION BY SECTION 25100, 25102 OR 25105 OF THE CALIFORNIA
CORPORATIONS CODE. THE RIGHTS OF ALL PARTIES TO THIS AGREEMENT ARE EXPRESSLY
CONDITIONED UNLESS THE SALE IS SO EXEMPT.



                                       7
<PAGE>



               IN WITNESS WHEREOF, the parties hereto have executed this
Agreement as of the day and year first above written.

                                    SPINE WAVE, INC.


                                    By:    /s/  Mark LoGuidice,
                                           -------------------------------------
                                           Mark LoGuidice,
                                           President and Chief Executive Officer

                       Address:     12230 El Camino Real, Suite 300
                                    San Diego, California 92130



                                    PURCHASER

                                    Protein Polymer Technologies, Inc.

                                    /s/ J. Thomas Parmeter
                                    --------------------------------------------
                                           J. Thomas Parmeter
                                           President and Chief Executive Officer

                       Address:     10655 Sorrento Valley Road
                                    San Diego, California 92121



                  [SIGNATURE PAGE TO STOCK PURCHASE AGREEMENT]

<PAGE>



                                    EXHIBIT A
                                    ---------

                                   [AMENDMENT]



<PAGE>

Portions of this document have been redacted pursuant to a Request
for Confidential Treatment filed with the Securities and Exchange Commission.
Redacted portions are indicated with the notation "*****"



                AMENDMENT NO. 1 TO SUPPLY AND SERVICES AGREEMENT

        THIS AMENDMENT NO. 1 TO SUPPLY AND SERVICES AGREEMENT (this "Amendment")
is made and  entered  into as of the 12th day of February  2002 (the  "Effective
Date") by and between PROTEIN POLYMER TECHNOLOGIES, INC., a Delaware corporation
("PPTI") and SPINE WAVE, INC., a Delaware corporation ("Company") and amends the
terms and conditions of that certain Supply and Services  Agreement  dated as of
April 12, 2001 by and between the Company and PPTI (the "Original Agreement").


                              W I T N E S S E T H:


        WHEREAS, PPTI and Company are parties to the Original Agreement;

        WHEREAS,  PPTI and the Company  desire to amend  certain of the terms of
the Original Agreement;

        NOW,  THEREFORE,  in  consideration  of the mutual  covenants  contained
herein and for other good and valuable consideration,  the receipt,  sufficiency
and  adequacy  of which is hereby  acknowledged,  the  parties  hereto  agree as
follows:



<PAGE>



        A. Definitions and Sections.  All capitalized terms used but not defined
in this  Amendment  shall have the  meanings  ascribed  thereto in the  Original
Agreement.  Section  and  Schedule  references  in this  Amendment  shall  be to
Sections of and Schedules to the Original Agreement, as amended hereby.

        B. Amendment of Section 2(a) and 2(b). Sections 2(a) and 2(b) are hereby
deleted and amended and restated to read as follows:

               (a) During the Initial  Term,  PPTI shall  provide  Materials  to
        Company and Company shall purchase  Materials from PPTI for Non-Clinical
        Use as set forth in Amended and Restated Schedule 1 attached hereto.

               (b) During the Start-Up Term subsequent to the Initial Term, PPTI
        shall  provide  Materials  to the  Company and  Company  shall  purchase
        Materials from PPTI as set forth in the Amended and Restated  Schedule 2
        attached hereto.

        C.  Amendment of Section 5.1. The last sentence of Section 5.1 is hereby
deleted  and amended and  restated  to read as follows:  PPTI shall  provide the
accommodations  listed  above to the  Company  at no  additional  charge  to the
Company.

        D. Amendment of Sections 6(c) and 6(d). Sections 6(c) and (d) are hereby
deleted and amended and restated to read as follows:



<PAGE>



               (c) The parties agree that the Additional  Term began on February
        12, 2002 and will end on February 11,  2003,  absent a default or breach
        of the Original  Agreement as amended hereby. On the first day of March,
        2002  (subject to a fifteen (15)  business day grace  period) and on the
        first day of each of the next  five (5)  consecutive  months  thereafter
        (e.g. April 1, 2002 through August 1, 2002, both inclusive), the Company
        shall pay PPTI the sum of*****. On the first day of September,  2002 and
        on the first day of each  consecutive  month  thereafter  throughout the
        remainder of the  Additional  Term,  the Company  shall pay PPTI the sum
        of*****.  PPTI shall  throughout the  Additional  Term continue to apply
        project  accounting  to  the  work  under  the  Original  Agreement  and
        within***** after the close of each month during the Additional Term and
        within*****  following the termination of the Original  Agreement,  PPTI
        shall  provide  the  Company  with a  statement  (i)  setting  forth the
        Materials,  Additional  Services,  Design  Services  and other  services
        provided to Company by PPTI and the related  costs,  and (ii)  itemizing
        any  applicable  credits  due to the  Company  as set  forth  below  and
        additional  payments  due PPTI  pursuant  to  paragraph  (d) below.  The
        Company shall make any payment due to PPTI within*****  after receipt of
        the statement. Any credit due to the Company shall be***** during or for
        the Additional Term, exclusive of the monthly payments specified above.

               (d)  Notwithstanding  anything  else  to the  contrary  contained
        herein, the parties agree that:

                      (i) Upon  expiration  of the Initial  Term, if the Company
               has paid the Minimum  Payment  each month of the Initial Term and
               has  not  received  an  aggregate  of  Initial   Services  and/or
               Materials equal to*****,  the Company shall receive a credit from
               PPTI equal  to***** which may be applied  toward  payments by the
               Company  to  PPTI  for  Materials,  Additional  Services,  Design
               Services  and/or  other  services  provided  hereunder  after the
               Additional Term.

                      (ii) Any credit due the  Company  upon  expiration  of the
               Additional   Term,  may  be  applied  to  Materials,   Additional
               Services,   Design  Services   and/or  other  services   provided
               hereunder  during the***** period following the expiration of the
               Additional  Term  or  as  the  Company  may  reasonably   request
               following  consultation with PPTI. With respect to the Injectable
               Disk Nucleus  product,  for  each*****  period  subsequent to the
               Additional  Term,  the amount  charged by PPTI to the Company for
               aggregate actual***** costs per R&D personnel***** costs for each
               of the*****  set forth in the Amended  and  Restated  Schedule 5,
               or***** Cost per each Qualified Lot, shall not exceed***** during
               the prior***** period.

                      (iii) Intentionally omitted.


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


<PAGE>



                      (iv) During the Additional  Term,  specific  external PPTI
               expenses  authorized  in  writing  by  the  Company  for  special
               supplies,  services,  or equipment in an amount greater than*****
               in the  aggregate  per  activity  or  task  shall  be paid by the
               Company to PPTI  within ten (10) days of  delivery  of an invoice
               therefor from or on account of PPTI.


                      (v) During the Additional Term, the***** cost component of
               PPTI's*****  Cost for R&D personnel shall be  determined*****  as
               follows: (a) the***** PPTI*****  cost*****costs*****  costs,*****
               by (b) the***** during the*****.  However,  during the Additional
               Term,  PPTI shall assess costs  incurred by Company  using a*****
               cost per R&D personnel***** and at the end of the Additional Term
               or  upon  termination  of  the  Original  Agreement,  PPTI  shall
               calculate the actual***** cost per R&D personnel*****  during the
               Additional Term (or applicable  portion  thereof).  To the extent
               that  the  amounts  paid  by the  Company  hereunder  exceed  the
               actual*****  cost per R&D  personnel*****,  the Company  shall be
               entitled to a credit which may be applied as provided above.  The
               Company shall pay to PPTI  within***** of invoice after the close
               of the  Additional  Term (or  applicable  portion  thereof)  such
               amount,  if any by which the aggregate  actual*****  cost per R&D
               personnel***** exceeds the amounts paid by the Company hereunder,
               provided, however, that Company shall not be liable for aggregate
               actual***** cost per R&D personnel*****  that exceeds the amounts
               paid by the Company  hereunder by more than*****  unless the*****
               number of R & D personnel during the*****  the***** number of R &
               D personnel as of*****in  which case Company  shall not be liable
               for  aggregate  actual*****  cost  per  R&D  personnel*****  that
               exceeds  the  amounts  paid  by the  Company  hereunder  by  more
               than*****.

                      (vi) During the Additional  Term, for each of the***** set
               forth in the  Amended  and  Restated  Schedule  5, PPTI shall not
               charge Company for***** costs that exceed by more than***** costs
               for  each  of  such*****  as  of  the*****,   unless  during  the
               Additional  Term PPTI***** as defined in the***** dated March 21,
               2002, in which case PPTI shall not charge Company  for***** costs
               that  exceed  by  more  than*****  the*****  costs  for  each  of
               such***** as of*****

                      (vii) On or before the first day of August, 2002, PPTI and
               the Company  shall  review the  estimated  Materials,  Additional
               Services, Design Services and/or other services to be provided by
               PPTI to the Company for the remainder of the


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


<PAGE>



               Additional Term. The Company agrees to adjust the monthly payment
               as  required  to cover any  material  underpayment,  taking  into
               account*****   specified  in  paragraph  (c)  above*****  by  the
               Company.

        E. Schedules. The Amended and Restated Schedules 1, 2, 3, and 5 attached
hereto  supercede and replace in their  entirety the existing  Schedules 1, 2, 3
and 5 to the Original Agreement.

        F. Continuing Agreement.  Each party hereby acknowledges that there have
occurred no defaults  under or breaches of the  Original  Agreement by the other
party.  Except as otherwise provided herein,  the Original  Agreement  continues
unchanged and in full force and effect.

        G.  Conflicts.  This Amendment  supersedes all prior or  contemporaneous
understandings or agreements,  whether written or oral,  between the Company and
the PPTI with respect to such  amendment.  In the event of any conflict  between
the terms of this Amendment and the terms of the Original  Agreement,  the terms
of this Amendment shall govern and control.

        H.  Further  Assurances.  The  Company  and PPTI agree to  execute  such
further instruments, agreements and document, and to take such further action as
may be reasonably necessary to carry out the intent of this Amendment.

        I. Counterparts. This Amendment may be executed by the parties hereto in
one or more  counterparts and all of said  counterparts  taken together shall be
deemed to constitute one and the same instrument.

        J. Governing Law. This Amendment  shall be governed by, and construed in
accordance with, the laws of the State of California.


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


<PAGE>




        IN WITNESS  WHEREOF,  the parties have caused this  Amendment to be duly
executed as of the day and year first above written.


        SPINE WAVE, INC.


        By:/s/ Mark LoGuidice
           -----------------------------------------
            Mark LoGuidice
            President and Chief Executive Officer


        PROTEIN POLYMER TECHNOLOGIES, INC.



        By:/s/ J. Thomas Parmeter
           -----------------------------------------
            J. Thomas Parmeter
            President and Chief Executive Officer


<PAGE>



                         AMENDED AND RESTATED SCHEDULE 1

           MATERIALS DURING THE INITIAL TERM AND FOR NON-CLINICAL USE
           ----------------------------------------------------------



        During the Initial Term, PPTI shall supply  Materials to the Company for
Non-Clinical Use at the Company's request as follows:


------------------------------------------------- ------------------------------
Material supplied by PPTI:                        Cost to Company:
------------------------------------------------- ------------------------------
For each Qualified Lot of Material (except as     ***** per each Qualified Lot
set forth below)
------------------------------------------------- ------------------------------
For each Off-the-Shelf Lot of Material            *****
------------------------------------------------- ------------------------------
For each Additional Qualified Lot of Material     ***** per each Qualified Lot
------------------------------------------------- ------------------------------

"Additional  Qualified Lot" shall mean any Qualified Lot of Material  ordered by
Company (i) after the Company orders***** Qualified Lots of Material and (ii) in
excess  of***** for any*****  period;  provided  that,  for purposes of clarity,
orders in  any*****  shall be counted  toward  any*****  period  with either the
immediately preceding or immediately subsequent*****, but not both.

"Off-the-Shelf  Lot" shall mean any lot of Material existing in PPTI's inventory
as of the date of the Agreement.


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


                                 Schedule 1 - 1

<PAGE>



                         AMENDED AND RESTATED SCHEDULE 2

          MATERIALS DURING THE START-UP TERM SUBSEQUENT TO THE INITIAL
                            TERM AND FOR CLINICAL USE
          ------------------------------------------------------------


        During the Start-Up Term subsequent to the Initial Term or for purchases
of Materials made for Clinical Use during the Start-Up Term,  PPTI shall provide
Materials to the Company at the Company's request as follows:

<TABLE>
<S>                                               <C>
------------------------------------------------- -----------------------------------------------
Material:                                         Cost:
------------------------------------------------- -----------------------------------------------
For each Qualified Lot* supplied by PPTI for      ***** per each Qualified Lot,*****
non-clinical use (except as set forth below)
------------------------------------------------- -----------------------------------------------
For each Excess Qualified Lot* supplied by PPTI   ***** per each Excess Qualified
for non-clinical use                                    Lot,*****
------------------------------------------------- -----------------------------------------------
For each Qualified Lot* supplied by PPTI for      ***** per each Qualified Lot,*****
clinical use
------------------------------------------------- -----------------------------------------------
Qualified Lot* supplied by third-party contract   ***** per each Qualified Lot
manufacturer
------------------------------------------------- -----------------------------------------------
</TABLE>


"Excess Qualified Lot" shall mean any Qualified Lot of Material ordered by
Company when PPTI accepts orders for more than***** of Material in any*****
period during the Additional Term, any such***** determined consecutively from
the start of the Additional Term.

*****


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


                                 Schedule 2 - 1

<PAGE>



                         AMENDED AND RESTATED SCHEDULE 3

                           QUALITY CONTROL PROCEDURES
                           --------------------------


------------------------------------------------------ -------------------------
                 Procedure/Test                             ***** Cost* ($)
------------------------------------------------------ -------------------------
*****
------------------------------------------------------ -------------------------

* Current as of the Effective Date of the Original Agreement; to be adjusted
from time to time to reflect changes in PPTI's actual***** Cost or***** Cost, as
applicable.


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


                                 Schedule 3 - 1
<PAGE>



                         AMENDED AND RESTATED SCHEDULE 5
                               ADDITIONAL SERVICES
                               -------------------



        During the Additional Term, PPTI shall provide to Company,  at Company's
request,  the***** set forth below or***** subject to Company's reasonable prior
approval,  for the  stated***** an IDE to FDA approval for the  Injectable  Disc
Nucleus product.


----------------------------------------- --------------------------------------
*****
----------------------------------------- --------------------------------------


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.



<PAGE>



                                    EXHIBIT B
                                    ---------


                  CERTIFICATE OF ACKNOWLEDGEMENT OF TERMINATION
                               OF VOTING AGREEMENT

               The undersigned parties to that certain Voting Agreement dated as
of April 12, 2001, as amended through the date hereof (the "Voting Agreement"),
by and among Spine Wave, Inc., Protein Polymer Technologies, Inc. and Windamere
Venture Partners, LLC, hereby acknowledge and consent to the following:

                      Pursuant to Sections 5 and 7 of the Voting Agreement,
        effective as of the effective date of this Certificate of
        Acknowledgement of Termination of Voting Agreement, the Voting Agreement
        is hereby terminated in its entirety for all time, is of no further
        force and effect and no party thereto shall have any remaining rights or
        obligations thereunder.

               This Certificate of Acknowledgement of Termination of Voting
Agreement has been executed and is effective as of March __, 2002 and may be
executed in more than one counterpart, each of which shall be deemed an
original, but all of which shall constitute one and the same instrument.

                                    SPINE WAVE, INC.



                                    By:
                                        ----------------------------------------
                                           Mark LoGuidice,
                                           President and Chief Executive Officer



                                    PROTEIN POLYMER TECHNOLOGIES, INC.



                                    By:
                                        ----------------------------------------
                                           J. Thomas Parmeter,
                                           President and Chief Executive Officer



                                    WINDAMERE VENTURE PARTNERS, LLC



                                    By:
                                        ----------------------------------------

                                    Its:
                                        ----------------------------------------



<PAGE>



                                    EXHIBIT C
                                    ---------

                                LETTER AGREEMENT


                                 March 21, 2002



Protein Polymer Technologies, Inc.
10655 Sorrento Valley Road
San Diego, CA  92121
Attn:  J. Thomas Parmeter, President and Chief Executive Officer

        Re:    License Agreement.

Dear Mr. Parmeter:

        This letter agreement (the "Letter Agreement") sets forth our
understanding regarding the treatment of a certain termination provision under
that certain License Agreement dated as of April 12, 2001, as amended, by and
between Spine Wave, Inc. ("Spine Wave") and Protein Polymer Technologies, Inc.
("PPTI"). This Letter Agreement is being entered into in connection with and as
consideration under the Stock Purchase and Vesting Agreement of even date
herewith between Spine Wave and PPTI.

        1. Termination of License Agreement. Notwithstanding the provisions of
Section 9.2(b) of the License Agreement, and subject to the limitation set forth
in the following sentence, Spine Wave and PPTI hereby agree that if Spine Wave
has not closed its currently contemplated Series A Preferred Stock Financing on
or before April 12, 2002, PPTI shall not, at any time prior to May 12, 2002,
exercise its right to terminate the License Agreement pursuant to Section 9.2(b)
thereof if and provided that Spine Wave has paid to PPTI all payments due and
payable as of April 1, 2002 under that certain Supply and Services Agreement
dated as of April 12, 2001, as amended through the date hereof.

        2. License Agreement. Except as otherwise modified in this Letter
Agreement, the License Agreement and the terms and conditions therein remain
unchanged and in full force and effect.

        3. Amendments and Waivers. Any term of this Letter Agreement may be
amended and the observance of any term of this Letter Agreement may be waived
only with the written consent of Spine Wave and PPTI.

        4. Counterparts. This Letter Agreement may be executed in two
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.



<PAGE>




        5. Governing Law. This Letter Agreement shall be construed and the
rights of the parties shall be determined in accordance with the substantive
laws of the State of California, without regard to its conflict of laws
principles.



                                    Very truly yours,

                                    SPINE WAVE, INC.



                                    By:
                                           -------------------------------------
                                           Mark LoGuidice,
                                           President and Chief Executive Officer


AGREED AND ACCEPTED:

PROTEIN POLYMER TECHNOLOGIES, INC.


By:
        ------------------------------------
        J. Thomas Parmeter,
        President and Chief Executive Officer




<PAGE>



                                    EXHIBIT D
                                    ---------

                      ASSIGNMENT SEPARATE FROM CERTIFICATE



               FOR VALUE RECEIVED, Protein Polymer Technologies, Inc. hereby
sells, assigns and transfers unto _____________________________,
______________________ (______) shares of the Common Stock of Spine Wave, Inc.,
standing in its name on the books of said corporation represented by Certificate
No. __ herewith and does hereby irrevocably constitute and appoint
__________________ attorney to transfer said stock on the books of the
within-named corporation with full power of substitution in the premises.
Dated: _________________, _____.

                                            Protein Polymer Technologies, Inc.



                                            ------------------------------------
                                            By:
                                            Its:

               This Assignment Separate from Certificate was executed in
conjunction with the terms of a Stock Purchase Agreement between the above
assignor and Spine Wave, Inc. dated March__, 2002.



<PAGE>



                                    EXHIBIT E
                                    ---------

                                   MILESTONES

Purchaser shall acquire a vested interest in a portion of the Stock and the
Repurchase Option shall lapse with respect to a portion of the Stock upon
Purchaser's attainment of the following Milestones:

1.      ***** MILESTONE: Purchaser shall acquire a vested interest in, and the
        Repurchase Option shall lapse with respect to, 100,000 shares of the
        Stock on such date,***** as Purchaser has accomplished the following:

                      a.     Completion of the***** testing and initiation*****
                             testing necessary,***** to file a submission for an
                             investigational device exemption with the United
                             States Food and Drug Administration (the "FDA")
                             including the requirement set forth in***** and the
                             initiation of the tests listed***** on Appendix A
                             attached hereto.

        Purchaser agrees to use commercially reasonable efforts to attain each
        element of the***** Milestone before*****

        2. ***** MILESTONE: Purchaser shall acquire a vested interest in, and
        the Repurchase Option shall lapse with respect to, 150,000 shares of the
        Stock on the later of such date,***** as Purchaser has accomplished both
        of the following:

                      a.     Completion of***** necessary,***** for the
                             submission of an investigational device exemption
                             application for a pilot study of the IDN with the
                             FDA including the requirements set forth in *****
                             on Appendix A attached hereto; and

                      b.     Purchaser has provided the Company with an adequate
                             inventory of***** to complete the pilot clinical
                             study*****

        Purchaser agrees to use commercially reasonable efforts to attain each
        element of the***** Milestone before*****

        3.***** MILESTONE: Provided that Purchaser has first attained each of
        the***** Milestone and the***** Milestone***** Purchaser shall acquire a
        vested interest in, and the Repurchase Option shall lapse with respect
        to, the remaining 150,000 shares of the Stock on the later of such
        date,*****


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


<PAGE>



        (provided that if the Company does not notify Purchaser of the Company's
        desire for Purchaser to develop***** manufacturing capability and
        provide the Company with an adequate supply of***** to complete the
        pivotal clinical trials***** as Purchaser has accomplished both of the
        following.

                      a.     At the Company's request and expense, Purchaser has
                             provided the Company with*****, satisfactory in the
                             Company's reasonable discretion, of a*****
                             manufacturer for production of*****; and

                      b.     Purchaser has provided the Company with an adequate
                             inventory***** to complete the pivotal clinical
                             trial*****

        Purchaser agrees to use commercially reasonable efforts to attain each
        element of the *****Milestone before*****.


-----------
***** Material is confidential and has been omitted and filed
separately with the Securities and Exchange Commission.


<PAGE>



                                   APPENDIX A
                                   ----------

1. Completion of all Acute Toxicity testing and reports (see Pre-clinical Tests
   below)
2. Completion of all Chronic Testing with ninety (90) day report (see
   Pre-clinical Tests below)
3. Characterization of the Master Cell Bank for the protein selected for the IDN
4. Characterization of the protein selected for the IDN
5. Characterization of the specified IDN material
6. Qualification of the protein manufacturing process for submission of an
   investigational device exemption application for a pilot clinical study of
   the IDN with the FDA
7. Successful results, in the Company's reasonable judgment, from the mechanical
   testing


                               Preclinical Tests*

Acute Tests

------------------------ --------------------- --------------------- -----------
Test                     Article Form          Animal Model          Follow up
------------------------ --------------------- --------------------- -----------
Cytotoxicity             MEM extract           In-vitro L929         48 hours
------------------------ --------------------- --------------------- -----------
Sensitization            Saline/CSO extracts   Guinea pig            22 days
------------------------ --------------------- --------------------- -----------
Intracutaneous           Saline/CSO extracts   Rabbit                7 days
reactivity
------------------------ --------------------- --------------------- -----------
Systemic toxicity        Saline/CSO extracts   Mouse                 72 hours
------------------------ --------------------- --------------------- -----------
Pyrogenicity LAL         Saline extract        In vitro              N/A
Endotoxin
------------------------ --------------------- --------------------- -----------
Irritation               In-situ cured         Rabbit (muscle)       5 days
                         implant
------------------------ --------------------- --------------------- -----------
Genotoxicity -           Saline/DMSO extracts  In vitro              N/A
Bacterial reverse
mutation
------------------------ --------------------- --------------------- -----------
Genotoxicity             Saline/DMSO extracts  In vitro              N/A
Chromosome aberration
------------------------ --------------------- --------------------- -----------
Genotoxicity             Saline/DMSO extracts  In vitro              N/A
Micronucleus test
------------------------ --------------------- --------------------- -----------


Chronic Tests

------------------------ --------------------- --------------------- -----------
Test                     Article Form          Animal Model          Follow up
------------------------ --------------------- --------------------- -----------
Subchronic Neural        In-situ cured         Rabbit                30 days
toxicity                 implant               (peri-sciatic nerve
                                               injection)
------------------------ --------------------- --------------------- -----------
Implantation             In-situ cured         Sheep intradiscal     90 day
                         implant               injection             interim
                                                                     1 year
                                                                     total
------------------------ --------------------- --------------------- -----------
Chronic toxicity         In-situ cured         Rabbit                7 days
                         implant
------------------------ --------------------- --------------------- -----------

* The tests required are subject to change based on feedback from the FDA.