Intraoperative Consultation During Orthopedic Surgery

Tumors of bone and soft tissue invariably require clinical history and radiologic evaluation for definitive diagnosis. Increasingly, core needle biopsy (CNB) is the primary method for obtaining tissue for diagnosis due to advancement of intraprocedural imaging techniques, safety, and cost effectiveness. The major role of intraoperative frozen section is to determine adequacy of tissue for diagnosis in those cases in which core needle biopsy is not possible or is inconclusive. The secondary role in this setting is to triage material for ancillary studies, such as cytogenetics and flow cytometry. Additional important applications of frozen section include suspected infection, such as infected joint prostheses, and evaluating marrow margins to rule out intramedullary tumor extension.

The goals of intraoperative consultation (IOC) during orthopedic surgery are focused on addressing several key issues:

• 1.

  Nature of the lesion, e.g., inflammatory, infectious, primary sarcoma, metastatic tumor or hematopoietic malignancy

• 2.

  Tissue adequacy for diagnostic purposes

• 3.

  Tissue triage for ancillary investigations which may be required for diagnostic, prognostic, and therapeutic studies

  • a.

    Microbiologic cultures

  • b.

    Cytogenetic studies

  • c.

    Flow cytometry

  • d.

    Electron microscopy, uncommonly

  • e.

    Direct immunofluorescence, rarely

• 4.

  Evaluation of resection margins, usually grossly

Although the above settings may appear limited, the diagnostic challenges within each category can be quite variable and present significant intraoperative difficulties. The preoperative preparation by the pathologist is one of the most important and often least emphasized contributions to proper IOC consultation. Therefore, in our practice, the preoperative preparation by the pathologist is one of the most important and often least emphasized contributions to proper IOC. This discussion raises a critical point regarding the intraoperative need for classification of the process versus a diagnosis that is specific enough to enable proper management but is short of a definitive diagnosis. In general, the following questions can be used to help sort out this distinction:

• 1.

  Does the histologic appearance of the diagnostic tissue (based on the tissue obtained and the ancillary studies available) correlate with the clinical and radiologic impression?

• 2.

  If diagnostic tissue is thought to be obtained, is the process inflammatory or neoplastic?

• 3.

  If inflammatory, are the findings nonspecific or are there granulomas or organisms which permit a more specific classification?

• 4.

  In revision arthroplasty, is a significant neutrophilic infiltrate present?

• 5.

  In cases which are thought to be neoplastic microscopically, is the tumor benign, malignant or of uncertain biologic potential?

• 6.

  If malignant, then is it primary sarcoma, a metastasis, or a hematopoietic malignancy?

  • a.

    In general, specific subclassification of a primary bone or soft tissue tumor is less important for management than assigning it to one of the categories above.

  • b.

    In a subset of cases, it is simply not possible to make a definitive diagnosis either because of the limitations of cutting bone or because of the intrinsic rarity of and heterogeneity within bone and soft tissue tumors; deferral is appropriate with the caveat that additional tissue may be necessary for a final diagnosis.

The remainder of the chapter will be divided into the categories of bone and soft tissue. Bone will be subdivided into revision arthroplasty, inflammatory/infectious, and neoplastic cases.