Intuitive Surgical, a leader in robotic surgical systems, experienced a notable rise in its stock price early Friday following the announcement of impressive second-quarter results, which exceeded market expectations. The company's growth can be attributed to significant increases in procedure volumes across various segments. In the June quarter, adjusted earnings per share reached $1.78, marking an increase from $1.50 in the same period last year.
Analysts had anticipated earnings of $1.54, indicating that Intuitive Surgical outperformed expectations on this front. The company's revenue also saw a commendable growth of 14%, totaling $2.01 billion, surpassing the street's forecast of $1.97 billion. As a result, the stock surged by 5.7% in premarket trading. Diving deeper into the financials, the instruments and accessories segment demonstrated impressive performance, with revenue increasing by 16% to $1.24 billion.
This growth was largely driven by a remarkable 17% rise in the number of procedures utilizing the da Vinci robotic surgery systems, coupled with an astounding 82% increase in Ion procedure volume. However, it should be noted that this growth was somewhat tempered by variations in customer buying patterns. In the United States, procedure volumes rose by 14%, largely influenced by advances in general surgery, as noted by Chief Financial Officer Jamie Samath during an earnings call, which was referenced in a transcript from Capital IQ.
Furthermore, outside the U.S., procedure volumes surged by 22%, benefiting significantly from continued expansions in general surgery, gynecology, and thoracic procedures, showcasing the company's strong international presence. The revenue derived from system sales reached $448.2 million, an increase from $392.7 million a year earlier.
During this quarter, Intuitive Surgical successfully placed 341 da Vinci surgical systems, including 70 of the next-generation da Vinci 5 systems, a slight increase from 331 placements in the same quarter last year. Additionally, service revenue rose to $317.3 million compared to $287.3 million in the previous year. On the cost side, total operating expenses rose to $805.4 million, up from $708.7 million last year.
The increase in expenses is attributed to the ongoing benefits associated with planned leverage in supporting operational functions, as explained by Samath to analysts. Looking forward, Intuitive Surgical is optimistic about its growth trajectory. The company anticipates procedure growth of 15.5% to 17% for 2024, revising their previous guidance of a 14% to 17% increase.
Brian King, the head of investor relations, indicated that the lower end of the forecast assumes potential challenges in bariatric procedures, particularly due to ongoing physician strikes in Korea and delays in tenders within China. Additionally, emerging domestic robotic systems may impact capital placements and subsequently, procedure growth. For the fiscal year, the pro forma gross profit margin is projected to be between 68.5% and 69% of net revenue, an improvement from earlier forecasts of 67% to 68%.
In contrast, pro forma operating expense growth is expected to range from 10% to 13%, a slight revision from the previous guidance of 11% to 15%. Overall, these results reflect the robust operational health of Intuitive Surgical amid a rapidly evolving healthcare landscape, and investors will be keenly watching how the company navigates potential headwinds ahead..