Focal hole versus screw stimulation to prevent false negative results in detecting pedicle breaches during spinal instrumentation

ObjectiveWe describe a stimulus-evoked EMG approach to minimize false negative results in detecting pedicle breaches during lumbosacral spinal instrumentation.MethodsIn 36 patients receiving 176 lumbosacral pedicle screws, EMG threshold to nerve root activation was determined using a focal probe inserted into the pilot hole at a depth, customized to the individual patients, suitable to position the stimulating tip at the point closest to the tested nerve root. Threshold to screw stimulation was also determined.ResultsMean EMG thresholds in 161 correctly fashioned pedicle instrumentations were 7.5 mA ± 2.46 after focal hole stimulation and 21.8 mA ± 6.8 after screw stimulation. Direct comparison between both thresholds in individual pedicles showed that screw stimulation was always biased by an unpredictable leakage of the stimulating current ranging from 10 to 90%. False negative results were never observed with hole stimulation but this was not true with screw stimulation.ConclusionsFocal hole stimulation, unlike screw stimulation, approaches absolute EMG threshold as shown by the lower normal limit (2.6 mA; p < 0.05) that borders the upper limit of threshold to direct activation of the exposed root.SignificanceThe technique provides an early warning of a possible pedicle breakthrough before insertion of the more harmful, larger and threaded screw.     

Larotrectinib for the treatment of TRK fusion solid tumors

Introduction: TRK fusions occur across a wide range of cancers in children and adults. These fusions drive constitutive expression and ligand-independent activation of the TRK kinase and are oncogenic. Larotrectinib is the first highly potent and selective small molecule ATP competitive inhibitor of all three TRK kinases to enter clinical development.

Areas covered: This review covers the current preclinical and clinical evidence for TRK inhibitors for TRK fusion cancers, focusing on larotrectinib.

Expert commentary: Larotrectinib has demonstrated a remarkable 75% centrally confirmed objective response rate in patients with TRK fusion cancers in phase 1 and phase 2 clinical trials with generally mild side effects. Responses appear independent of the patient’s age, underlying histology, and specific fusion partner and are durable in many patients. Larotrectinib is likely to be the first FDA-approved histology-agnostic molecularly targeted therapy. The evolving role of molecular profiling of advanced cancers is discussed.     

Does Timing of Primary Total Hip Arthroplasty Prior to or After Lumbar Spine Fusion Have an Effect on Dislocation and Revision Rates?

Background

Patients undergoing primary total hip arthroplasty (THA) following lumbar spine fusion have an increased incidence of dislocation compared to those without prior lumbar fusion. The purpose of this study is to determine if timing of THA prior to or after lumbar fusion would have an effect on dislocation and revision incidence in patients with both hip and lumbar spine pathology.

Posterior thoracolumbar fusion in a patient with Kleefstra Syndrome related scoliosis: The first case reported

Spine deformities could be considered a possible manifestation of the childhood hypotonia, typical feature of Kleefstra Syndrome (KS). There is a paucity of literature describing posterior spinal fusion in the Kleefstra syndrome patient. For patients who develop severe scoliotic curve, bracing is often ineffective and surgery is recommended. We report the first corrective surgery for scoliosis in one patient with KS.We describe a case of 13-year-old female with severe developmental scoliosis in KS. Preoperative examination showed a thoracolumbar scoliosis with left convex thoracic curve (T3-T9, 97°) and right convex thoracolumbar curve (T9-L3, 88°). Posterior correction, pedicle screw fixation and bone graft fusion T3-L5 was performed. Postoperatively, the thoracic curve was corrected to 33° while the thoracolumbar one to 26° and better standing posture was obtained. Six month follow-up images showed no loosening of the hardware. The patient is still in our follow-up program.Scoliosis seems to be a rare evenience of the severe hypotonia of patients with KS. We report the first case of scoliosis in KS treated successfully with surgery. Corrective surgery for spinal deformity, such as scoliosis, could help in posture and improve the quality of life especially in complicated patients such as syndromic ones.     

Introduction and evaluation of a novel multi-camera surface topography system

BackgroundSurface topography can be used for the evaluation of spinal deformities without any radiation. However, so far this technique is limited to posterior trunk measurements due to the use of a single posterior camera.Research questionPurpose of this study was to introduce a new multi camera surface topography system and to test its reliability and validity.MethodsThe surface topograph uses a two-camera system for imaging and evaluating the subjects front and back simultaneously. Inter- and intra-rater reliability was tested on 40 human subjects by two observers. For validation human, subjects were scanned by MRI and surface-topography. For additional validation we used a phantom with an anthropomorphic body which was scanned by CT and surface topography.ResultsInter- (0.97−0.99) and intra-rater reliability (0.81−0.98) testing revealed good and excellent results in the detection of the body surface structures and measurement of areas and volumes. CT based validation revealed good correspondence between systems in the imaging and evaluation of the phantom model (0.61–10.52 %). Results on validation of human subjects revealed good to moderate results in the detection and measurements of almost all body surface structures (1.36–13.34 %). Only measurements using jugular notch as a reference showed moderate results in validity (0.62–27.5%) testing.SignificanceWe have introduced a novel and innovative surface topography system that allows for simultaneous anterior and posterior trunk measurements. The results of our reliability and validity tests are satisfactory. However, in particular around the jugular notch region further improvements in the surface topography reconstruction are needed.