The introduction of a new robot for assistance in ophthalmic surgery.

This paper introduces the design and development of a new robotic system to assist surgeons performing ophthalmic surgeries. The robot itself is very compact and similar to an average human hand in size. Its primary application is intraocular micromanipulation in order to overcome the existing challenges in treatment of diseases like Retinal Vein Occlusion (RVO). The novel hybrid mechanism designed for this robot allows microscale motions and is stable in the presence of vibrations common in operation room (OR). The robotic system can be easily integrated into standard operation rooms and does not require modification of conventional surgical tools. This compact microsurgical system is suitable for mounting on the patient's head and thereby, solves the problem of patient motion. The compatibility of the robotic system with a real world surgical setup was evaluated and confirmed in this work.

Kryptonite bone cement prevents pathologic sternal displacement.

BACKGROUND: Wire cerclage closure of sternotomy is the standard of care despite evidence of pathologic sternal displacement (> 2 mm) during physiologic distracting forces (coughing). Postoperative functional recovery, respiration, pain, sternal dehiscence, and infection are influenced by early bone stability. This translational research report provides proof-of-concept (part A) and first-in-man clinical data (part B) with use of a triglyceride-based porous adhesive to rapidly enhance the stability of conventional sternal closure. METHODS: In part A, fresh human cadaver blocks were subjected to midline sternotomy and either conventional wire closure or modified adhesive closure. After 24 hours at 37 degrees C, using a biomechanical test apparatus, a step-wise increase in lateral distracting force simulated physiologic stress. Sternal displacement was measured by microdisplacement sensors. In part B, a selected clinical case series was performed and sternal perfusion assessed by serial single photon emission computed tomography imaging. RESULTS: Wire closure resulted in measurable bony displacement with increasing load. Pathologic displacement (> or = 2 mm) was observed in all regional segments at loads 400 newton (N) or greater. In contrast, adhesive closure completely eliminated pathologic displacement at forces 600 N or less (p < 0.001). In patients, adhesive closure was not associated with adverse events such as adhesive migration, embolization, or infection. There was excellent qualitative correlation between cadaver and clinical computed tomographic images. Sternal perfusion was not compromised by adhesive closure. CONCLUSIONS: This first-in-man series provides proof-of-concept indicating that a novel biologic bone adhesive is capable of rapid sternal fixation and complete elimination of pathologic sternal displacement under physiologic loading conditions. A randomized clinical trial is warranted to further define the potential risks and benefits of this innovative technique.

Childhood acute lymphoblastic leukemia (ALL) presenting with severe osteolysis: a model to study leukemia-bone interactions and potential targeted therapeutics.

Interference with the molecular mechanisms that generate tumor supportive niches in the bone microenvironment is a rational approach to inhibit the growth of hematological malignancies. However, the advancement of knowledge in this area has been slowed down by the lack of in vitro models to facilitate the screening of potential candidate agents. The rare cases of acute lymphoblastic leukemia (ALL) in children presenting with extensive bone involvement may represent an exaggerated form of some aspects of the normal tumor-bone interactions. Thus, these cases can provide insight into processes that are otherwise challenging to uncover. The authors describe the case of a 6-year-old child who presented with severe osteopenia that resolved at the time of leukemic remission. Compared to control sera, serum taken at disease presentation contained increased levels of a group of osteolytic cytokines and was effective in activating preosteoclast cells in culture. Based on these findings, the authors describe an experimental model to identify agents that would interfere with leukemia mediated osteolytic process.

Remediation of sentence processing deficits in aphasia using a computer-based microworld.

Byng (1988) has argued that some aphasic patients who show problems in sentence comprehension are unable to "map" a syntactic analysis of the sentence form onto the thematic roles specified by the verb or preposition in the sentence. In Byng's study, therapy aimed at improving the mapping process as applied to sentences containing locative prepositions led to improvements not only in the comprehension of such sentences but also in the comprehension of reversible verb sentences. In the present study, 14 aphasic patients were selected for having problems with sentence-picture matching involving reversible verb and preposition sentences. These problems were shown to be stable across three pre-intervention assessments. All assessments were computer-based and involved the matching of written sentences to pictures. A small vocabulary was used in assessment and therapy which involved a "microworld" of three characters (ball, box, and star) which could engage in a limited number of actions and could occupy a limited set of spatial relationships. Before therapy began, all the patients were given an assessment battery which included a 40-item Verb Test and a 40-item Preposition Test. The patients were then divided into two groups, A and B. Group A received two 1-hr sessions of therapy per week for 3 weeks aimed at improving the comprehension of verb sentences, then a second full assessment, followed by the same amount of therapy aimed at improving the comprehension of preposition sentences, and finally a third assessment. Group B received the preposition therapy first, followed by the verb therapy. The therapy involved the patient and therapist interacting with the computer, either assembling pictures to match written sentences ("picture-building mode") or assembling sentences to match pictures ("sentence-building mode"). Group A showed a classical "cross-over" treatment outcome. Performance on treated verb sentences improved during verb therapy and was retained when therapy switched to preposition sentences. Performance on treated preposition sentences was unaffected by verb therapy but improved when therapy switched to the processing of prepositions. Performance on untreated verb and preposition sentences showed a similar pattern, though the improvements observed were not as great. Improvement was also shown on a paper-based "Real World Test" which involved a wider range of more naturalistic sentences. Performance on a third aspect of sentence comprehension which the patients also had difficulty with, namely the comprehension of morphology, remained unchanged throughout, providing further evidence that the effects obtained were treatment-specific. The results of Group B were less clear cut. Comprehension of both verb and preposition sentences improved during the period that prepositions were being treated then remained static during verb treatment. Comprehension of morphology remained unchanged throughout. At the level of the individual patient, the majority of patients obtained higher scores on both the Verb Test and the Preposition Test after therapy, but only three patients showed improvements on both verbs and prepositions that were statistically significant. Six patients showed significant improvements on verbs but not prepositions while one showed the opposite pattern. Only three patients failed to show so much as a borderline improvement on either verbs or prepositions. Finally, seven of the patients returned for an additional assessment 5 months after completing the therapy. These patients, who had demonstrated significant improvements during the therapy, were shown to have maintained their improved comprehension skills.

Clinical education: the supervisory process.

This investigation of the supervisory process was designed to extend the first author's (MMcG) previous work that had resulted in categories for analysis of clinical competence in student therapists. The supervisory interactions between five students and their clinicians were video-taped and analysed. Participants' perceptions of the dyad were rated using visual analogue scales. The findings indicated that clinicians' verbal comments could be assigned to the categories previously identified. A further analysis of three of these categories revealed that seven interview strategies were used by the clinicians in the process of supervision. Supervisors appeared to be more accurate in estimating the extent of students' participation in the conference whereas students tended to make a more realistic estimation of the level of positive feedback. Pointers for future research are suggested.