Low-Cost, Three-Dimensionally-Printed, Anatomical Models for Optimization of Orbital Wall Reconstruction.

BACKGROUND: Orbital blowout fracture reconstruction often requires an implant, which must be shaped at the time of surgical intervention. This process is time-consuming and requires multiple placement trials, possibly risking complications. Three-dimensional printing technology has enabled health care facilities to generate custom anatomical models to which implants can be molded to precisely match orbital anatomy. The authors present their early experience with these models and their use in optimizing orbital fracture fixation. METHODS: Maxillofacial computed tomographic scans from patients with orbital floor or wall fractures were prospectively obtained and digitally reconstructed. Both injured-side and mirrored unaffected-side models were produced in-house by stereolithography printing technique. Models were used as templates for molding titanium reconstruction plates, and plates were implanted to reconstruct the patients' orbital walls. RESULTS: Nine patients (mean age, 15.5 years) were included. Enophthalmos was present in seven patients preoperatively and resolved in six patients with surgery. All patients had excellent conformation of the implant to the fracture site on postoperative computed tomographic scan. Postoperative fracture-side orbital volumes were significantly less than preoperative, and not significantly different from unfractured-side orbital volumes. Total model preparation time was approximately 10 hours. Materials cost was at most $21. Plate bending time was approximately 60 seconds. CONCLUSIONS: Patient-specific orbital models can speed the shaping of orbital reconstruction implants and potentially improve surgical correction of orbital fractures. Production of these models with consumer-grade technology confers the same advantages as commercial production at a fraction of the cost and time. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Quick Calculation of Breast Resection Mass Using the Schnur Scale.

In 1991, Dr Paul Schnur and his colleagues published an article correlating the weight of breast tissue to be removed in a breast reduction operation with the total body surface area (BSA) of the patient. They presented a very cogent argument for selecting three groups of patients: those with medical indications for operation, those who merit review, and those whose operation could be considered cosmetic. The Schnur Sliding Scale is widely used by insurance companies in the western United States in the process of preauthorizing breast reduction operations, and its use may be spreading eastward. The Schnur group presented a nomogram for calculating BSA and a scale in the form of a table for guiding a determination of whether the patient is a reconstructive patient as opposed to an aesthetic patient. We have combined the scale and the BSA nomogram for a simplified nomogram calculator that facilitates rapid determination of anticipated tissue weight of resection for a patient of a given size. This calculator yields the required weight of tissue to remove with just knowledge of the patient's height and weight and the use of a straight edge. We demonstrate and compare performance of this calculation by hand and by nomogram. There is ample evidence that the practice of applying the Schnur Sliding Scale may be prohibitive to symptomatic patients seeking reduction mammaplasty and should be abandoned. While this practice continues, our simplified Schnur Sliding Scale nomogram is meant to help easily determine the insurer-required minimum breast resection weight and thereby both improve patient counseling prior to planning surgery and assist the surgeon with achieving insurer reimbursement for the procedure while avoiding rejected claims.