Target Identification for Stereotactic Thalamotomy Using Diffusion Tractography

BACKGROUND: Stereotactic targets for thalamotomy are usually derived from population-based coordinates. Individual anatomy is used only to scale the coordinates based on the location of some internal guide points. While on conventional MR imaging the thalamic nuclei are indistinguishable, recently it has become possible to identify individual thalamic nuclei using different connectivity profiles, as defined by MR diffusion tractography. METHODOLOGY AND PRINCIPAL FINDINGS: Here we investigated the inter-individual variation of the location of target nuclei for thalamotomy: the putative ventralis oralis posterior (Vop) and the ventral intermedius (Vim) nucleus as defined by probabilistic tractography. We showed that the mean inter-individual distance of the peak Vop location is 7.33 mm and 7.42 mm for Vim. The mean overlap between individual Vop nuclei was 40.2% and it was 31.8% for Vim nuclei. As a proof of concept, we also present a patient who underwent Vop thalamotomy for untreatable tremor caused by traumatic brain injury and another patient who underwent Vim thalamotomy for essential tremor. The probabilistic tractography indicated that the successful tremor control was achieved with lesions in the Vop and Vim respectively. CONCLUSIONS: Our data call attention to the need for a better appreciation of the individual anatomy when planning stereotactic functional neurosurgery

Histone Deacetylase 3 Depletion in Osteo/Chondroprogenitor Cells Decreases Bone Density and Increases Marrow Fat

Histone deacetylase (Hdac)3 is a nuclear enzyme that contributes to epigenetic programming and is required for embryonic development. To determine the role of Hdac3 in bone formation, we crossed mice harboring loxP sites around exon 7 of Hdac3 with mice expressing Cre recombinase under the control of the osterix promoter. The resulting Hdac3 conditional knockout (CKO) mice were runted and had severe deficits in intramembranous and endochondral bone formation. Calvarial bones were significantly thinner and trabecular bone volume in the distal femur was decreased 75% in the Hdac3 CKO mice due to a substantial reduction in trabecular number. Hdac3-CKO mice had fewer osteoblasts and more bone marrow adipocytes as a proportion of tissue area than their wildtype or heterozygous littermates. Bone formation rates were depressed in both the cortical and trabecular regions of Hdac3 CKO femurs. Microarray analyses revealed that numerous developmental signaling pathways were affected by Hdac3-deficiency. Thus, Hdac3 depletion in osterix-expressing progenitor cells interferes with bone formation and promotes bone marrow adipocyte differentiation. These results demonstrate that Hdac3 inhibition is detrimental to skeletal health

Post-traumatic distal humerus non-union: Open reduction and internal fixation: long-term results

The objective of this paper is to evaluate the long-term functional results achieved after open reduction and internal fixation of 24 distal humerus non-unions. Non-unions were extra-articular-extracapsular (11 cases), extra-articular-intracapsular (8 cases) and intra-articular (5 cases). Preoperative elbow range of motion averaged 45°. Time between original trauma and revision surgery averaged 14 months. Stabilisation methods varied according to type and location of the non-union. Follow-up averaged 46 months (range: 18–108). Elbow range of motion at last examination averaged 98°. Flexion averaged 110° and extension loss averaged 17°. The disabilities of the arm, shoulder and hand (DASH) score averaged 16 points. Secondary transposition of the ulnar nerve was necessary in three cases. Sixteen patients reported no pain at last examination, seven had mild pain and one had moderate pain. Distal humerus non-unions present different characteristics; consequently, surgical treatment must be individualised for each patient. Even though they are demanding procedures, bony union and good long-term functional results were achieved