The use of 3D models to improve sinus augmentation outcomes - A case report.

Sinus augmentation is a predictable procedure that is often required when restoring the posterior maxilla with dental implants. Even with high success rates, careful pre-surgical planning is crucial. A 3D model is a valuable aid for the clinician as it allows for pre-operative simulation, which can reduce surgical time, reduce the risk of intra-operative complications and decrease the potential for error. The aim of this case report is to focus on how such a model is useful when undertaking a sinus augmentation procedure with simultaneous implant placement.

Behavioral signs of ongoing pain and cold allodynia in a rat model of neuropathic pain.

Previous studies by our laboratory established a rat model of neuropathic pain which displayed long-lasting heat hyperalgesia and mechanical allodynia that are sympathetically maintained. The present study was undertaken to extend our earlier findings by examining additional behavioral signs of ongoing pain and cold allodynia in our animal model and testing their sympathetic dependency. Neuropathic surgery was done by tightly ligating the L5 and L6 segmental spinal nerves of rats unilaterally. In addition to the behavioral signs of heat hyperalgesia and mechanical allodynia observed before, these rats displayed signs of ongoing pain (lasting at least 10 weeks) and cold allodynia (lasting at least 16 weeks). These behaviors were reduced markedly after surgical lumbar sympathectomy. The results of the present study, together with the previous study, suggest that our animal model exhibits neuropathic pain behaviors including ongoing pain, heat hyperalgesia, mechanical allodynia and cold allodynia. Since all of these behavioral signs are sympathetically maintained, our model represents a model for sympathetically maintained pain.

An experimental model for peripheral neuropathy produced by segmental spinal nerve ligation in the rat.

We attempted to develop an experimental animal model for peripheral neuropathic pain. Under sodium pentobarbital anesthesia, both the L5 and L6 spinal nerves (group 1) or the L5 spinal nerve alone (group 2) of one side of the rat were tightly ligated. For comparison, a parallel study was conducted with another group of rats (group 3) which received a partial tight sciatic nerve ligation, a paradigm developed previously as a neuropathy model. Withdrawal latencies to application of radiant heat to the foot were tested for the next 16 weeks in all 3 groups. Sensitivity of the hind paw to mechanical stimulation was tested with von Frey filaments. The general behavior of each rat was noted during the entire test period. Results suggested that the surgical procedure in all 3 groups produced a long-lasting hyperalgesia to noxious heat (at least 5 weeks) and mechanical allodynia (at least 10 weeks) of the affected foot. In addition, there were behavioral signs of the presence of spontaneous pain in the affected foot. Therefore, we believe we have developed an experimental animal model for peripheral neuropathy using tight ligations of spinal nerves. The model manifests the symptoms of human patients with causalgia and is compatible with a previously developed neuropathy model. The present model has two unique features. First, the surgical procedure is stereotyped. Second, the levels of injured and intact spinal segments are completely separated, allowing independent experimental manipulations of the injured and intact spinal segments in future experiments to answer questions regarding mechanisms underlying causalgia.