**Exhibit 10.28****SUMMARY OF DIRECTOR COMPENSATION**Annual Retainer     Members of the Board of Directors of Symbion, Inc. (the “Company”) who are also officers oremployees of the Company receive no additional compensation, beyond that which they receive asofficers of the Company, for serving on the Company’s Board of Directors. Non-employee members ofthe Board receive a $20,000 annual retainer for serving on the Board. The chairperson of eachBoard committee receives a $4,000 annual retainer in addition to the Board retainer.Meeting Fees     Non-employee members of the Board of Directors receive (i) up to $10,000 per year forattendance (not including by telephone) at regularly scheduled Board meetings ($2,500 for eachmeeting), (ii) $1,000 per meeting of the Board attended by telephone, and (iii) $1,000 per meetingfor attendance (in person or by telephone) at Board committee meetings. Non-employee directors arereimbursed for expenses incurred in attending meetings of the Board and Board committees.Equity Incentives     In addition to the cash compensation discussed above, non-employee directors are also eligibleto receive equity awards granted by the Compensation Committee of the Board of Directors.     The Company maintains a Non-Employee Directors Stock Option Plan under which options topurchase shares of its Common Stock are available for issuance to the non-employee members of theBoard of Directors. Historically, each non-employee director of the Company has received an annualgrant of options to purchase a number of shares determined by the Compensation Committee. Theoptions are exercisable at the fair market value of the Common Stock on the date of grant, and eachoption becomes fully exercisable one year from the date of grant. The options expire on theearlier of the date set forth in the option agreement (typically, seven or ten years from the dateof grant) or immediately upon a director’s termination on account of fraud, dishonesty or otheracts detrimental to the Company. In the event of any other termination of a director, any vestedoptions granted to the director may be exercised for a period of 12 months after termination. Upona change in the control of the Company, as described in the Non-Employee Directors Stock OptionPlan, all options become immediately vested and exercisable.
 

 
     Non-employee directors are eligible to receive equity awards under the Company’s Long TermIncentive Plan. In 2007, the Compensation Committee intends to make an award of restricted stockto non-employee directors under the Long Term Incentive Plan in lieu of an option grant under theNon-Employee Directors Stock Option Plan. It is expected that the restricted stock will be awardedto non-employee directors on the date of the Company’s annual meeting and that it will vest over athree year period beginning on the date of grant provided that the director is serving as adirector of the Company on the vesting date. Upon a change in the control of the Company, asdescribed in the Non-Employee Directors Stock Option Plan, and certain other triggering events, allshares of restricted stock become immediately vested. The Compensation Committee may make awards tonon-employee directors in the future pursuant to the Long Term Incentive Plan in lieu of, or inaddition to, awards under the Non-Employee Directors Stock Option Plan.