As technology continues to reshape industries, the legal sector is witnessing transformative changes, particularly in Big Law. The integration of Artificial Intelligence (AI) tools in legal practice has emerged as a trend, shaking up traditional methods of operation. While AI holds the promise of efficiency and precision, it also presents ethical and operational challenges that law firms must navigate prudently.

AI algorithms are being leveraged to automate repetitive tasks such as document review, due diligence, and even predicting legal outcomes based on past cases. This not only reduces the workload of legal professionals but also allows them to focus on more complex tasks. For instance, Deloitte has integrated AI to enhance its legal auditing services, showcasing a significant reduction in time and costs.

However, the deployment of AI in legal practice isn't without its concerns. Ethical dilemmas surface when addressing bias in AI algorithms. In some instances, AI systems have exhibited tendencies to replicate existing biases present in judicial decisions. This necessitates that law firms maintain a vigilant approach to AI deployment, ensuring systems are constantly monitored and refined.

Moreover, the operational impact extends to the structure of law firms. With AI taking over certain tasks, the need for junior associates performing traditional roles is decreasing. Firms like Ernst & Young are re-evaluating their personnel strategy, emphasizing efficient AI integration while re-skilling employees for strategic tasks.

The legal industry is witnessing a shift in client expectations with the rise in AI adoption. Clients demand faster services with utmost accuracy, and firms that leverage AI effectively are at the forefront in fulfilling these demands. This dynamic is compelling firms to adopt cutting-edge technologies, adapting to the evolving legal landscape while adhering to ethical frameworks and privacy laws.

From a regulatory perspective, law firms must navigate the complex web of data privacy laws, especially when dealing with cross-border transactions. Compliance with these regulations is crucial, ensuring that client data remains protected while leveraging AI's capabilities.

In conclusion, while AI serves as a powerful ally in Big Law, it requires careful integration with a focus on ethical considerations and operational restructuring. The future of legal practice hinges on the ability of firms to adapt, harnessing AI’s benefits while remaining committed to ethical standards. Real-life examples, such as those from leading firms like PricewaterhouseCoopers, highlight the potential of AI when combined with strategic oversight.