Automatic registration with continuous pose updates for marker-less surgical navigation in spine surgery.

Established surgical navigation systems for pedicle screw placement have been proven to be accurate, but still reveal limitations in registration or surgical guidance. Registration of preoperative data to the intraoperative anatomy remains a time-consuming, error-prone task that includes exposure to harmful radiation. Surgical guidance through conventional displays has well-known drawbacks, as information cannot be presented in-situ and from the surgeon's perspective.

A Statistical Shape Model-Based Analysis of Periacetabular Osteotomies: Technical Considerations to Achieve the Targeted Correction.

Background: Classic and reverse Bernese periacetabular osteotomy (PAO) have been shown to be effective for the treatment of developmental dysplasia of the hip (by classic PAO), severe acetabular retroversion (by reverse PAO), and some protrusio acetabuli (by reverse PAO). Especially in severe cases with higher degrees of correction, a relevant overlap between the osteotomized fragment and the pelvis might occur, leading to necessary fragment translation. The aim of the present study was to analyze the necessary translation as a function of the degree of correction using a statistical mean model of the pelvis according to the technique (classic PAO or reverse PAO).

Spinal decompression with patient-specific guides.

Background Context: Patient-specific instruments (PSI) have been well established in spine surgery for pedicle screw placement. However, its utility in spinal decompression surgery is yet to be investigated.

Purpose: The purpose of this study was to investigate the feasibility and utility of PSI in spinal decompression surgery compared with conventional freehand (FH) technique for both expert and novice surgeons.

Similar scapular morphology in patients with dynamic and static posterior shoulder instability.

Background: There is evidence that specific variants of scapular morphology are associated with dynamic and static posterior shoulder instability. To this date, observations regarding glenoid and/or acromial variants were analyzed independently, with two-dimensional imaging or without comparison with a healthy control group. Therefore, the purpose of this study was to analyze and describe the three-dimensional (3D) shape of the scapula in healthy and in shoulders with static or dynamic posterior instability using 3D surface models and 3D measurement methods.

Malpositioning of patient-specific instruments within the possible degrees of freedom in high-tibial osteotomy has no considerable influence on mechanical leg axis correction.

Purpose: Patient-specific instruments (PSIs) are helpful tools in high tibial osteotomy (HTO) in patients with symptomatic varus malalignment of the mechanical leg axis. However, the precision of HTO can decrease with malpositioned PSI. This study investigates the influence of malpositioned PSI on axis correction, osteotomy, and implant placement.