<?xml version="1.0" encoding="utf-8"?>
<Return returnVersion="2023v5.0" xmlns="http://www.irs.gov/efile" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2024-05-02T18:53:07-07:00</ReturnTs>
    <TaxPeriodEndDt>2023-12-31</TaxPeriodEndDt>
    <ReturnTypeCd>990EZ</ReturnTypeCd>
    <TaxPeriodBeginDt>2023-01-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>921345276</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>COMPREHENSIVE SPINE STUDY GROUP</BusinessNameLine1Txt>
      </BusinessName>
      <BusinessNameControlTxt>COMP</BusinessNameControlTxt>
      <PhoneNum>4192368831</PhoneNum>
      <USAddress>
        <AddressLine1Txt>303 Belvedere Ave</AddressLine1Txt>
        <CityNm>Belvedere</CityNm>
        <StateAbbreviationCd>CA</StateAbbreviationCd>
        <ZIPCd>94920</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>Lee Tan</PersonNm>
      <PersonTitleTxt>Treasure</PersonTitleTxt>
      <PhoneNum>4192368831</PhoneNum>
      <SignatureDt>2024-05-02</SignatureDt>
    </BusinessOfficerGrp>
    <SigningOfficerGrp>
      <PersonFullName>
        <PersonFirstNm>Lee</PersonFirstNm>
        <PersonLastNm>Tan</PersonLastNm>
      </PersonFullName>
      <SSN>999009999</SSN>
    </SigningOfficerGrp>
    <IRSResponsiblePrtyInfoCurrInd>1</IRSResponsiblePrtyInfoCurrInd>
    <AdditionalFilerInformation>
      <TrustedCustomerGrp>
        <TrustedCustomerCd>0</TrustedCustomerCd>
        <OOBSecurityVerificationCd>11</OOBSecurityVerificationCd>
        <LastSubmissionRqrOOBCd>0</LastSubmissionRqrOOBCd>
        <AuthenticationAssuranceLevelCd>AAL2</AuthenticationAssuranceLevelCd>
      </TrustedCustomerGrp>
    </AdditionalFilerInformation>
    <TaxYr>2023</TaxYr>
    <BuildTS>2023-04-26 12:10:37Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="3">
    <IRS990EZ documentId="R000001" referenceDocumentId="R000003" softwareId="23018249" softwareVersionNum="v1.00">
      <MethodOfAccountingCashInd>X</MethodOfAccountingCashInd>
      <ScheduleBNotRequiredInd>X</ScheduleBNotRequiredInd>
      <WebsiteAddressTxt>http://spinecssg.org</WebsiteAddressTxt>
      <Organization501c3Ind referenceDocumentId="R000002">X</Organization501c3Ind>
      <TypeOfOrganizationCorpInd>X</TypeOfOrganizationCorpInd>
      <GrossReceiptsAmt>129380</GrossReceiptsAmt>
      <InfoInScheduleOPartIInd>X</InfoInScheduleOPartIInd>
      <ContributionsGiftsGrantsEtcAmt>129380</ContributionsGiftsGrantsEtcAmt>
      <ProgramServiceRevenueAmt>0</ProgramServiceRevenueAmt>
      <MembershipDuesAmt>0</MembershipDuesAmt>
      <InvestmentIncomeAmt>0</InvestmentIncomeAmt>
      <SaleOfAssetsGrossAmt>0</SaleOfAssetsGrossAmt>
      <CostOrOtherBasisExpenseSaleAmt>0</CostOrOtherBasisExpenseSaleAmt>
      <GainOrLossFromSaleOfAssetsAmt>0</GainOrLossFromSaleOfAssetsAmt>
      <GamingGrossIncomeAmt>0</GamingGrossIncomeAmt>
      <FundraisingGrossIncomeAmt fndrsngEventContriPrevRptAmt="0">0</FundraisingGrossIncomeAmt>
      <SpecialEventsDirectExpensesAmt>0</SpecialEventsDirectExpensesAmt>
      <SpecialEventsNetIncomeLossAmt>0</SpecialEventsNetIncomeLossAmt>
      <GrossSalesOfInventoryAmt>0</GrossSalesOfInventoryAmt>
      <CostOfGoodsSoldAmt>0</CostOfGoodsSoldAmt>
      <GrossProfitLossSlsOfInvntryAmt>0</GrossProfitLossSlsOfInvntryAmt>
      <OtherRevenueTotalAmt>0</OtherRevenueTotalAmt>
      <TotalRevenueAmt>129380</TotalRevenueAmt>
      <GrantsAndSimilarAmountsPaidAmt>0</GrantsAndSimilarAmountsPaidAmt>
      <BenefitsPaidToOrForMembersAmt>0</BenefitsPaidToOrForMembersAmt>
      <SalariesOtherCompEmplBnftAmt>0</SalariesOtherCompEmplBnftAmt>
      <FeesAndOtherPymtToIndCntrctAmt>0</FeesAndOtherPymtToIndCntrctAmt>
      <OccupancyRentUtltsAndMaintAmt>0</OccupancyRentUtltsAndMaintAmt>
      <PrintingPublicationsPostageAmt>0</PrintingPublicationsPostageAmt>
      <OtherExpensesTotalAmt>48636</OtherExpensesTotalAmt>
      <TotalExpensesAmt>48636</TotalExpensesAmt>
      <ExcessOrDeficitForYearAmt>80744</ExcessOrDeficitForYearAmt>
      <NetAssetsOrFundBalancesBOYAmt>0</NetAssetsOrFundBalancesBOYAmt>
      <OtherChangesInNetAssetsAmt>0</OtherChangesInNetAssetsAmt>
      <NetAssetsOrFundBalancesEOYAmt>80744</NetAssetsOrFundBalancesEOYAmt>
      <CashSavingsAndInvestmentsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>80744</EOYAmt>
      </CashSavingsAndInvestmentsGrp>
      <LandAndBuildingsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </LandAndBuildingsGrp>
      <OtherAssetsTotalDetail>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </OtherAssetsTotalDetail>
      <Form990TotalAssetsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>80744</EOYAmt>
      </Form990TotalAssetsGrp>
      <SumOfTotalLiabilitiesGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </SumOfTotalLiabilitiesGrp>
      <NetAssetsOrFundBalancesGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>80744</EOYAmt>
      </NetAssetsOrFundBalancesGrp>
      <PrimaryExemptPurposeTxt>Non-for profit Medical research organization to advance understanding spine care</PrimaryExemptPurposeTxt>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>The Comprehensive Spine Study Group (CSSG) is a group of highly trained spine surgeons dedicated to answering questions and forming solutions for the advancement of spine surgery and the treatment of spinal conditions. We are committed to leveraging big data to change the paradigm of how clinical research is being performed and generating the highest quality published research on spine surgery.</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>0</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>48630</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <TotalProgramServiceExpensesAmt>48630</TotalProgramServiceExpensesAmt>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Joseph Osorio</PersonNm>
        <TitleTxt>President</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>10</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Lee Tan</PersonNm>
        <TitleTxt>Treasure</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>10</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>Jun Kim</PersonNm>
        <TitleTxt>Secretary</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>10</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <ActivitiesNotPreviouslyRptInd>0</ActivitiesNotPreviouslyRptInd>
      <ChgMadeToOrgnzngDocNotRptInd>0</ChgMadeToOrgnzngDocNotRptInd>
      <OrganizationHadUBIInd>0</OrganizationHadUBIInd>
      <SubjectToProxyTaxInd>0</SubjectToProxyTaxInd>
      <OrganizationDissolvedEtcInd>0</OrganizationDissolvedEtcInd>
      <DirectIndirectPltclExpendAmt>0</DirectIndirectPltclExpendAmt>
      <Form1120PolFiledInd>0</Form1120PolFiledInd>
      <MadeLoansToFromOfficersInd>0</MadeLoansToFromOfficersInd>
      <TaxImposedUnderIRC4911Amt>0</TaxImposedUnderIRC4911Amt>
      <TaxImposedUnderIRC4912Amt>0</TaxImposedUnderIRC4912Amt>
      <TaxImposedUnderIRC4955Amt>0</TaxImposedUnderIRC4955Amt>
      <EngagedInExcessBenefitTransInd>0</EngagedInExcessBenefitTransInd>
      <TaxImposedOnOrganizationMgrAmt>0</TaxImposedOnOrganizationMgrAmt>
      <TaxReimbursedByOrganizationAmt>0</TaxReimbursedByOrganizationAmt>
      <ProhibitedTaxShelterTransInd>0</ProhibitedTaxShelterTransInd>
      <StatesWhereCopyOfReturnIsFldCd>MO</StatesWhereCopyOfReturnIsFldCd>
      <BooksInCareOfDetail>
        <BusinessName>
          <BusinessNameLine1Txt>CSSG</BusinessNameLine1Txt>
        </BusinessName>
        <USAddress>
          <AddressLine1Txt>303 Belvedere Ave</AddressLine1Txt>
          <CityNm>Belvedere</CityNm>
          <StateAbbreviationCd>CA</StateAbbreviationCd>
          <ZIPCd>94920</ZIPCd>
        </USAddress>
        <PhoneNum>4192368831</PhoneNum>
      </BooksInCareOfDetail>
      <ForeignFinancialAccountInd>0</ForeignFinancialAccountInd>
      <ForeignOfficeInd>0</ForeignOfficeInd>
      <DonorAdvisedFndsInd>0</DonorAdvisedFndsInd>
      <OperateHospitalInd>0</OperateHospitalInd>
      <TanningServicesProvidedInd>0</TanningServicesProvidedInd>
      <RelatedOrganizationCtrlEntInd>0</RelatedOrganizationCtrlEntInd>
      <TransactionWithControlEntInd>0</TransactionWithControlEntInd>
      <PoliticalCampaignActyInd>0</PoliticalCampaignActyInd>
      <LobbyingActivitiesInd>0</LobbyingActivitiesInd>
      <SchoolOperatingInd>0</SchoolOperatingInd>
      <TrnsfrExmptNonChrtblRltdOrgInd>0</TrnsfrExmptNonChrtblRltdOrgInd>
      <PartVIOfCompOfHghstPdEmplTxt>NONE</PartVIOfCompOfHghstPdEmplTxt>
      <PartVIHghstPdCntrctProfSrvcTxt>NONE</PartVIHghstPdCntrctProfSrvcTxt>
      <FiledScheduleAInd>1</FiledScheduleAInd>
    </IRS990EZ>
    <IRS990ScheduleA documentId="R000002" softwareId="23018249" softwareVersionNum="v1.00">
      <MedicalResearchOrganizationInd>X</MedicalResearchOrganizationInd>
      <HospitalNameAndAddressGrp>
        <SupportedOrganizationName>
          <BusinessNameLine1Txt>UCSF</BusinessNameLine1Txt>
        </SupportedOrganizationName>
        <CityNm>San Francisco</CityNm>
        <StateAbbreviationCd>CA</StateAbbreviationCd>
      </HospitalNameAndAddressGrp>
      <HospitalNameAndAddressGrp>
        <SupportedOrganizationName>
          <BusinessNameLine1Txt>UCSD</BusinessNameLine1Txt>
        </SupportedOrganizationName>
        <CityNm>San Diego</CityNm>
        <StateAbbreviationCd>CA</StateAbbreviationCd>
      </HospitalNameAndAddressGrp>
      <HospitalNameAndAddressGrp>
        <SupportedOrganizationName>
          <BusinessNameLine1Txt>Mount Sinai</BusinessNameLine1Txt>
        </SupportedOrganizationName>
        <CityNm>New York</CityNm>
        <StateAbbreviationCd>NY</StateAbbreviationCd>
      </HospitalNameAndAddressGrp>
    </IRS990ScheduleA>
    <IRS990ScheduleO documentId="R000003" softwareId="23018249" softwareVersionNum="v1.00">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990-EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>1) Bank Fees: $60.00 2) Accounting Firm Cost : $10,500 3) Research IRB setup cost - Western IRB: $1,285 4) Website maintenence and domain cost: $119.88 5) Database build payment: $17,430 6) Business Application Fee: $600 7) Payment to Code Technology for Patient reported outcome collection: $15,700 8) Meeting cost: $2,941.52 Total = $48,636.40</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>
