Ladies and gentlemen, thank you for standing by. Welcome to the Intuitive Surgical Q4 2017 earnings release conference call. At this time, all participants are in listen-only mode. Later, we will conduct a question and answer session, and instructions will be given at that time. If you should require assistance during the call, please press star followed by the zero. As a reminder, today's conference is being recorded. I would now like to turn the conference over to our first speaker, Calvin Darling, the Senior Director of Finance and Investor Relations. Please go ahead, sir.
Thank you. Good afternoon and welcome to Intuitive Surgical's fourth quarter earnings conference call. With me today, we have Gary Guthart, our President and CEO, and Marshall Mohr, our Chief Financial Officer. Note that Patrick Clingan, who has participated on these calls in the past, will not be joining us today. Patrick's scope of responsibilities in the company has grown over the past couple of years, and going forward, he will be dedicating less time to investor relations. Before we begin, I'd like to inform you that comments mentioned on today's call may be deemed to contain forward-looking statements. Actual results may differ materially from those expressed or implied as a result of certain risks and uncertainties.
These risks and uncertainties are described in detail in the company's Securities and Exchange Commission filings, including our most recent Form 10-K, filed on February 6th, 2017, and 10-Q, filed on October 20th, 2017. These filings can be found through our website or at the SEC's EDGAR database. Prospective investors are cautioned not to place undue reliance on such forward-looking statements. Please note that this conference call will be available for audio replay on our website at intuitivesurgical.com on the audio archive section under our investor relations page. In addition, today's press release and supplementary financial data tables have been posted to our website. Today's format will consist of providing you with highlights of our fourth quarter results as described in our press release announced earlier today, followed by a question and answer session. Gary will present the quarter's business and operational highlights.
Marshall will provide a review of our fourth quarter financial results. I will discuss procedures and clinical highlights and provide our financial outlook for 2018. Finally, we will host a question and answer session. With that, I'll turn it over to Gary.
Good afternoon, thank you for joining us on the call today. As you know, Intuitive is dedicated to the mission of expanding the availability of minimally invasive surgery, increasing its efficacy, and decreasing its invasiveness. The fourth quarter concluded a solid year in pursuit of this mission. During the year, we made progress in several areas, including accelerated use of our systems and the related growth in our installed base, along with the achievement of significant milestones in regional market access and product development. While we're pleased with our progress in the year, the opportunity for improvement in surgery is substantial, much work remains to be done. Global procedure growth was strong at approximately 17% in the fourth quarter and 16% for the full year.
Growth patterns and procedures were largely consistent through the year, with increased use of da Vinci in general surgery in the U.S., continued growth in urology in Europe and Japan, and multi-specialty growth in Korea and China. General surgery growth was led by hernia repair and colon resection, while mature procedures in the U.S., particularly prostatectomy, outperformed our expectations, predominantly due to macro trends in the prostate cancer market. Procedure growth in several countries, including Germany, Korea, and China, was healthy through the year, and adoption in Japan was solid for those procedures that have been reimbursed. This month, the Ministry of Health in Japan listed for reimbursement 12 procedures in which da Vinci could be used in addition to prostatectomy and nephrectomy, which are already reimbursed.
This is clearly a positive step regarding interest in da Vinci procedures in Japan, the final level of reimbursement has not been communicated. Calvin will review procedure trends and Marshall our progress in Japan in greater detail later in the call. Turning to capital placements, we expanded our da Vinci system offering this year with the launch of our da Vinci X surgical system, a response to customer need. da Vinci X delivers our fourth-generation robotics, imaging, and fully articulated instrumentation at an attractive entry price and procedure capability with logical upgrade pathways. Reception to X has been positive, catalyzing interest in robotics programs in price-sensitive markets. Taken together, our Gen4 products, da Vinci X, da Vinci Xi, and our future da Vinci SP, which is not yet cleared, represent a balanced and upgradable portfolio of choices for customers building or expanding their robotic surgery programs.
Our capital placement performance in 2017 accelerated relative to 2016, with growth in total placements rising 27%, from 537 in 2016 to 684 in 2017. Net of trade-ins and retirements, our da Vinci install base grew 13% over 2016 from 3,919 to 4,409. U.S. capital placement stood out in the year and the fourth quarter, largely driven by growth in general surgery. European placement performance in the fourth quarter was strong. Placements in the fourth quarter in Japan were also healthy, perhaps a one-time uptick in anticipation of broader reimbursement. Capital placements overall have been lumpy, we anticipate volatility in placements in 2018. Operating performance in the fourth quarter and for the full year exceeded our expectations, with strong performance in manufacturing efficiency, product quality, and cost reduction projects, and with average selling prices as expected.
Investments to deepen our regional capabilities and to develop new technologies and services were important in the past year. As our business strengthened, we increased some investments through 2017 to strengthen our corporate infrastructure and position us to benefit from increased scale. Turning to highlights of our fourth quarter operating results. Procedures grew approximately 17% over the fourth quarter of last year. We shipped 216 da Vinci surgical systems, up from 163 in the fourth quarter of 2016. Revenue for the quarter was $892 million, up 18%. Pro forma gross profit margin was 72.3%, compared to 71.1% in the fourth quarter last year. Instrument and accessory revenue increased to $457 million, up 18%. Total recurring revenue in the quarter was $618 million, representing 69% of total revenue. We generated a pro forma operating profit of $384 million in the quarter, up 20% from the fourth quarter of last year.
Pro forma net income was $298 million, up 23%. We concluded our accelerated share buyback program initiated in Q1 of 2017 at a weighted average price of $310 per share. Highlights of the full year 2017 are as follows. Procedures grew approximately 16% over 2016. We installed 684 systems in 2017, up from 537 in 2016. Revenue for the year was $3.1 billion, up 16%. Pro forma gross margin was 71.9% for the full year, compared with 71.6% for 2016. Total recurring revenue for the year was $2.2 billion, representing 72% of total revenue. Pro forma operating profit for the year was $1.3 billion, up 13% from 2016. Pro forma net income was $1 billion, up 19%. Marshall will take you through our finances in greater detail shortly. While Intuitive completed its 22nd year in 2017, I firmly believe that computer-assisted medical interventions are in their infancy.
A careful read of the clinical literature makes clear the need for more effective, less invasive, and lower total cost to treat solutions to many disease states. The rise of robotic technology, powerful computing, improved sensing, microfabrication, and molecular imaging enable new approaches to old problems. We have been investing in improvements, both incremental and revolutionary, towards the same. We anticipate continuing this investment trajectory in 2018. The opportunity to improve surgery using advanced technologies is now recognized broadly. We anticipate the entry of additional competitive systems into some regions of the world over the next several quarters. Customers appreciate choice. It is possible that sales cycles lengthen in some countries as customers evaluate more options. Our company has anticipated increased competition. We are focused on understanding the market's needs and excelling in delivering products and services today and in the future that meet them.
Turning to our da Vinci SP system, we submitted our 510(k) for urology last month. We call SP as a platform technology that allows high dexterity access with great 3D vision to confined surgical spaces. As we've discussed on prior calls, we plan first markets to include urologic surgery, head and neck surgery, and colorectal surgery. In 2017, SP was used in human trials in the U.S. and Hong Kong, completing cases spanning initial target procedures. We anticipate a phased launch of SP in 2018, pending clearance. We are also making good progress on our flexible robotics platform, first targeted to address the acute need in diagnosis of lung cancer, one of the most commonly diagnosed forms of cancer in the world and for which early detection is important. Our program hit its milestones in 2017, completing its first clinical experience in Australia.
Preliminary results were reported at the CHEST Conference in Q4 2017. Feedback from physicians evaluating our technology relative to existing and emerging alternatives has been strongly supportive of our efforts. Our design and operations teams are working hard to incorporate feedback, complete its production design and supply chain optimization, and complete validations for regulatory submissions. We do not expect revenue from our flexible robotics program in 2018. Our fourth-generation product platform has enabled greater access to our latest advanced instruments. Use and satisfaction with our stapling and energy products has been rising as Gen4 products have increased in the install base. Both stapling and energy instruments are important to surgeons, and we've been investing in broadening our product line and incorporating customer feedback in both areas. In the fourth quarter of 2017, we submitted our 510(k) application for our 60-millimeter stapler for da Vinci X and Xi.
Lastly, our imaging teams continue to explore new ways to identify tissue, including good progress in our molecular imaging program, as well as improvements to our endoscopes and image processing algorithms. We've been introducing improvements in our imaging hardware routinely and expect to continue to do so in 2018. Molecular imaging agents are long-term investments. We expect our lead agent to enter phase II trials in 2018. In closing, as we start 2018, our focus remains in completing the task we've set for ourselves. First, continued adoption of da Vinci in general surgery. Second, continued development of European markets and access to customers in Asia. Third, advancing our new platforms, imaging, advanced instruments, da Vinci SP, and our diagnostic platform. Finally, support for additional clinical and economic validation by global region. I'll now turn the call over to Marshall, who will review financial highlights.
Good afternoon. Overall, our fourth quarter financial performance was strong. I will start by describing highlights of this performance on a GAAP and non-GAAP or pro forma basis. I will also take you through our analysis of the impact of the U.S. 2017 Tax Cuts and Jobs Act on our financial results. As a reminder, our results are also posted on our website. Consistent with our preliminary press release on January 10th. Fourth quarter 2017 revenue was $892 million, an increase of 18% compared with $757 million for the fourth quarter of 2016, and an increase of 11% compared with the third quarter revenue of $806 million. In the fourth quarter, we completed the da Vinci X trade-out program offered to certain first-quarter customers. The impact of this program was to increase fourth quarter revenue by approximately $2 million and third-quarter revenue by approximately $21 million.
As mentioned earlier in the call, fourth quarter 2017 procedures increased approximately 17% compared with the fourth quarter of 2016, and increased 12% compared with last quarter. Procedure growth continues to be driven by general surgery in the U.S. and urology worldwide. Calvin will review details of procedure growth later in this call. Instrument and accessory revenue of $457 million increased 18% compared with last year, which is slightly higher than procedure growth. Instrument and accessory revenue realized per procedure was approximately $1,910, which is relatively unchanged compared to last year, reflecting increased advanced instrument usage, mostly offset by customer buying patterns. Systems revenue of $283 million increased 20% compared with the fourth quarter of 2016, primarily reflecting higher system placements. We placed 216 systems in the fourth quarter of 2017, compared with 163 systems in the fourth quarter of 2016, and 169 systems last quarter.
40 systems were placed under operating lease transactions in the current quarter, compared with 13 systems in the fourth quarter of 2016. Systems placed under operating leases represented 19% of system placements, compared with 8% last year. Our installed base of da Vinci systems ended the year at 4,409 systems, up 13% year-over-year. Consistent with recent trends, average system utilization continues to grow in the mid-single-digit range. Globally, our average selling price, which excludes the impact of operating leases and lease buyouts and revenue deferrals, was approximately $1.47 million, which is similar to the fourth quarter of 2016 and the same as last quarter. 51 or 24% of systems placed in the quarter were da Vinci X systems, compared with 16 or 9% of systems last quarter.
We are seeing demand for da Vinci X from cost-sensitive customers as well as customers wishing to upgrade to or standardize on our fourth generation technology. We believe that flexible financing programs like operating leases have allowed us to be more agile in meeting customer needs for systems. While the number of leases is difficult to predict in the short term, we expect the proportion of these types of arrangements will increase over time. Outside of the U.S., results were as follows. Fourth quarter revenue outside of the U.S. of $248 million increased 17% compared with both the fourth quarter of 2016 and the third quarter of 2017. OUS procedures grew approximately 21% compared with the fourth quarter of 2016. Outside the U.S., we placed 86 systems in the fourth quarter, compared with 63 in the fourth quarter of 2016 and 62 systems last quarter.
Current quarter system placements included 47 into Europe and 22 into Japan. 25 out of the 47 systems placed into Europe were X systems. Placements outside of the U.S. will continue to be lumpy as some of the OUS markets are in early stages of adoption. Some markets are highly seasonal, reflecting budget cycles or vacation patterns, and sales into some markets are constrained by government regulations. As Gary indicated, a committee of the MHLW in Japan has recommended 12 procedures for reimbursement. It is anticipated that by the end of this quarter, MHLW will determine the reimbursement levels for each procedure. The applicable opportunity for da Vinci surgery within this set of procedures is difficult to estimate at this time due to the uncertainty in reimbursement levels, as well as the perceived value of da Vinci relative to alternative surgical approaches.
With nearly 300 systems installed in Japan, the level of system expansion over the next year or so is difficult to predict. We expect system expansion in Japan to be modest in 2018. Moving on to the remainder of the P&L. The pro forma gross margin for the fourth quarter of 2017 was 72.3%, compared with 71.1% for the fourth quarter of 2016 and 71.8% for the third quarter of 2017. The increase compared with the third quarter primarily reflects lower manufacturing costs, partially offset by seasonally higher proportion of systems revenue. Future margins will also fluctuate based on the mix of our newer products, the mix of systems and instrument and accessory revenue, system ASPs, and our ability to further reduce product costs and improve manufacturing efficiency. Pro forma operating expenses increased 19% compared with the fourth quarter 2016 and increased 13% compared with last quarter.
The increase compared with the third quarter reflects increased variable compensation. Our spending was consistent with our plan, reflecting investments in da Vinci SP, catheter-based robotics, imaging and advanced instrumentation, and expansion of our OUS markets. These investments involve multiyear commitments. Our pro forma effective tax rate for the fourth quarter was 24.9%, compared with our expectations of 26.5%-28.5%. I will take you through the items included in our GAAP tax rate, including the impacts of the US Tax Act, in a minute. Our tax rates will fluctuate with changes in the mix of U.S. and OUS income, changes in tax rates made by local authorities, and with the impact of one-time items.
Our fourth quarter 2017 pro forma net income was $298 million, or $2.57 per share, compared with $242 million or $2.03 per share for the fourth quarter of 2016, and $324 million or $2.77 per share for the third quarter of 2017. All per share amounts reflect the three-for-one stock split affected in October. Third quarter 2017 GAAP and pro forma net income per diluted share benefited by $0.09 per share from the recognition of $21 million of deferred revenue, net of costs and income tax, and by $0.59 per share related to the tax reserve reversal of $68 million. I will now summarize our GAAP results.
Inclusive of the impacts of the US Tax Act, we incurred a GAAP net loss of $39 million or $0.45 per share for the fourth quarter of 2017, compared with GAAP net income of $204 million or $1.71 per share for the fourth quarter of 2016, and GAAP net income of $298 million or $2.55 per share for the third quarter of 2017. The following items are excluded from our fourth quarter pro forma net income but included in our GAAP net loss. $270 million or $2.41 per share, reflecting a 14% one-time tax for historical OUS earnings and profits under the US Tax Act. $48 million or $0.42 per share for the write-down of net deferred assets to reflect the reduction in corporate tax rates under the US Tax Act.
$20 million or $0.18 per share of excess tax benefits associated with employee stock awards, and $57 million of net charges or $0.51 per share associated with employee equity charges, IP charges, and legal settlements. Note that the IRS has not issued final tax rate regulations associated with the recent U.S. tax legislation. Therefore, impacts of the US Tax Act reflected in our fourth quarter results and our projection of future tax rates represent our best estimates of the impact of the US Tax Act and could change as tax regulations are finalized and interpreted. We ended the quarter with cash and investments of $3.8 billion, approximately the same as at September 30, 2017. During the quarter, cash generated from operations were mostly offset by a final payment of $274 million associated with the accelerated share repurchase agreement we entered in the first quarter.
Under that agreement, we purchased 7.3 million shares at approximately $310 per share. We have approximately $718 million remaining under the board buyback authorization. As a result of the 2017 Tax Act, we have the option to repatriate OUS cash with minimal tax impact. We have significant opportunity for growth outside of the U.S. We will evaluate the need to repatriate cash relative to our business and overall environment over time. With that, I'd like to turn it over to Calvin, who will go over procedure performance and our outlook for 2018.
Thank you, Marshall. Our overall fourth quarter procedure growth was 17% compared to 15% during the fourth quarter of 2016 and 15% last quarter. Our Q4 procedure growth was driven by strong results globally and 16% growth in U.S. procedures, reflecting broad-based strength across our procedure categories. Q4 likely benefited modestly from cases deferred out of Q3 due to hurricanes. In total, approximately 877,000 da Vinci procedures were performed in 2017, up about 16% for the year. In the U.S., general surgery on a run rate basis has surpassed gynecology as our largest specialty. Approximately 246,000 U.S. general surgery procedures were performed in 2017, up 32% compared to 2016. 2017 growth was again driven by hernia repair, ventral and inguinal combined, which continued to drive the most incremental cases and continued da Vinci adoption in colorectal procedures.
Early-stage adoption in bariatric procedures and growth across the general surgery category also contributed to growth. In U.S. gynecology, fourth quarter and full year 2017 procedures grew modestly year-over-year, with growth led by hysterectomy. We continue to see an increasing proportion of U.S. gynecology procedures being performed by physicians that specialize in complex benign and cancer surgery, who tend to be users of da Vinci systems. U.S. urology procedures exceeded our expectations for the fourth quarter and the year, driven by prostatectomy volumes. As a mature procedure category, we believe that our U.S. prostatectomy volumes have been tracking to the broader prostate surgery market, which has benefited from recent macro trends. In other U.S. procedures, adoption of lobectomies and other thoracic procedures was again strong during the fourth quarter and full year.
This set of procedures is particularly well served by our da Vinci Xi system and surgical staplers. Outside of the United States, approximately 233,000 procedures were performed in 2017, up approximately 21% in the fourth quarter and approximately 23% for the full year. Growth was driven by the continued adoption of da Vinci prostatectomy, with solid contributions from kidney procedures and earlier stage growth in general surgery and gynecology. Fourth quarter OUS procedure growth was slightly lower, largely reflecting leveling system utilization and moderating growth in China as we anticipate future system sales quota. The value proposition regarding any da Vinci procedure is based upon the differentiated clinical value that can be offered to patients compared to other treatment alternatives, including economic factors. Since the introduction of the da Vinci system, over 15,000 clinical papers have been published involving da Vinci surgery, including approximately 2,300 in 2017 alone.
As I mentioned in my procedure discussion, lung procedures in the U.S. have contributed to recent procedure growth. In November 2017, a team of investigators from the University of Southern California, the University of Michigan, Ann Arbor, Penn State Health, and Intuitive, published a large-scale study titled "Robotic-Assisted, Video-Assisted Thoracoscopic, and Open Lobectomy: Propensity Matched Analysis of Recent Premier Data" in the Annals of Thoracic Surgery. In the study, the Premier Healthcare database was analyzed for open video-assisted thoracoscopic, or VATS, and robotic-assisted lobectomies performed between January 1st, 2011, and September 30th, 2015. The results from this study show a continual increase in the number of robotic-assisted lobectomies during the study period. The combined total of robotic-assisted and VATS approaches accounted for more than half of the lobectomies in the U.S. database, indicating a strong trend towards adoption of minimally invasive approaches.
While the proportion of VATS remained virtually unchanged during the study period, the robotic rate grew as open declined. After propensity score matching, which controls for heterogeneity of patients in hospitals, the robotic-assisted cases were compared to VATS procedures in a sample size of 2,775 in each group, and robotic-assisted cases were compared to open with 2,951 patients in each group. Compared to open surgery, robotic-assisted lobectomy demonstrated statistically significant lower postoperative complication rate, shorter hospital stay, higher percentage of patients discharged to home, and lower hospital mortality rate. Compared to VATS, robotic-assisted surgery demonstrated statistically significant lower rate of conversion to thoracotomy, lower postoperative complication rate, shorter hospital stay, and a higher percentage of patients discharged to home. As we've said in the past, we continue to invest in clinical research in our key geographic markets to assess da Vinci surgery outcomes and help educate the market.
We support large-scale data registries, including those managed by the Americas Hernia Society Quality Collaborative and the Society of Gynecologic Oncology Clinical Outcomes Registry. As large da Vinci data sets accumulate in these registries and are compared to baseline results, the value of da Vinci surgery can be evaluated. We also support clinical research grants at SAGES, ASCRS, and the European Society of Coloproctology, as well as da Vinci fellowship programs with several surgical societies, which often yield clinical studies. I will now turn to our financial outlook for 2018. Starting with procedures, as described in our announcement earlier this month, 2017 total da Vinci procedures grew approximately 16% to roughly 877,000 procedures performed worldwide. During 2018, we anticipate full-year procedure growth within a range of 11%-15%.
We expect 2018 procedure growth to continue to be driven by U.S. general surgery and procedures outside of the United States, where we are still in earlier stages of adoption. We expect similar seasonal timing of procedures in 2018 as we've experienced in previous years, with Q1 being the seasonally weakest quarter as patient deductibles are reset. In Q1, we expect a modest procedure headwind compared to Q1 2017 as a result of our estimates of working days, mostly due to the timing of the Good Friday holiday. With respect to revenue, as we've mentioned previously, capital sales are ultimately driven by procedure growth, catalyzing hospitals to establish or expand robotic system capacity. Capital sales can vary substantially from period to period based upon many factors, including U.S. healthcare policy, hospital capital spending cycles, reimbursement and government quotas, product cycles, and competitive factors.
Within this framework, we'd expect 2018 capital placement seasonality to generally follow historical patterns by quarter. During the fourth quarter of 2017, 40 of the 216 systems shipped, or 19%, were under operating leases. In 2018, we'd expect the proportion of systems placed under operating leases to trend modestly up from there, with variation by quarter. Turning to gross profit. Our full-year 2017 pro forma gross profit margin was 71.9%. In 2018, we expect our pro forma gross profit margin to be within a range of between 70% and 71.5% net revenue. We're projecting a modestly lower gross profit margin in 2018, reflecting higher costs associated with new products. Our actual gross profit margin will vary quarter to quarter, depending largely on product and regional mix. Turning to operating expenses.
As Gary Guthart and Marshall Mohr described, in 2018, we will continue to make substantive investments in several strategic areas that are poised to benefit the company over the long run. As a result, we expect to grow 2018 pro forma operating expenses between 16% and 18% above 2017 levels. We expect our non-cash stock compensation expense to range between $225 million and $235 million in 2018, compared to $209 million in 2017. We expect our other income, which is comprised mostly of interest income, to total between $45 million and $55 million in 2018. With regard to income tax, incorporating projected impacts of the new U.S. tax law, we expect our 2018 pro forma income tax rate to be between 20% and 22% of pre-tax income. Note that in the future, as the IRS issues additional guidance and interpretation of the new tax law, our estimated rate may be impacted.
Our share count for calculated diluted EPS, pro forma EPS in Q4 was 117.4 million shares. In Q1, we expect our diluted share count to range between 117.6 million and 118.4 million shares. The actual diluted share count will depend on several factors, including the share price. That concludes our prepared comments. We will now open the call to your questions.
If there are any questions from the phone lines at this time, please press star followed by the one on your touch tone phone. You'll hear a tone indicating you have been placed in queue, and all questions will be polled in the order they are received. Once again, if there are any questions at this time, please press star followed by the one on your touch tone phone. Our first question today comes from the line of Bob Hopkins with Bank of America. Please go ahead.
Thanks very much. Appreciate the opportunity to ask a few questions here. Maybe just to start out on the product side, just want to make sure I have a good sense for what you're saying. Gary, I guess on the flexible endoscope platform, I realize you said no revenues in 2018, is there a scenario where we have any regulatory approvals for flexible endoscope in any major country, maybe towards the end of 2018?
Hi, Bob. We're not calling the clearance date yet of the flex platform. I'm pleased with where we are. We're working the plan. Our tradition with you has been to let you know when we do a submission, and that gives us a little bit better estimate of timelines, and I'd rather not guess in this setting. We're feeling good about it, but I don't have a date for you yet.
Okay. Feeling good about it, does that mean the potential for submissions in 2018?
No, I'm feeling good about the progress of the team and their ability to deliver on what we think this is capable of doing.
Okay. On your comments on Japan, I'm just curious, what do you assume for Japan in the current 11%-15%? Maybe said another way, if reimbursement comes in the way you would hope, does that suggest the potential for the higher end of that 11%-15%?
We haven't baked a lot of growth in there. Again, we don't really know at this point what the reimbursement levels are going to be, and therefore, that could vastly impact the procedure adoption curve. There's not a lot in there, but even then, the magnitude of Japan relative to the total world is not substantial. The highest growth drivers for us for next year really are general surgery procedures in the U.S. and urologic procedures outside of the U.S.
With these clearances, Bob, or reimbursements, I should say, it's going to be building a foundation time for us. There's going to be large investments made, or we have been making, and we're going to follow through on things like training surgeons and building the teams up to speed. It's really more about building a foundation here for the future in 2018 than a substantive contribution to the growth.
Gary, just real quickly, given the success you've had as a company in 2017 on the procedure side, I wanted to ask one quick question on how you view the market opportunity. In 2016 and 2017, your slide decks talked about 4 million accessible procedures worldwide for approved technologies. I'm just curious if you could update us on your latest thoughts on kind of the addressable procedures, where you stand today relative to that 4 million, given that you've got SP coming along with obviously other technologies.
Yeah. Fair question. As you described, I think for current products in the market and current countries in which we operate, I think our estimates are that we're not yet a quarter penetrated. Even with what our commercial teams have to do, we have plenty of upside. I think as you move time, whenever you talk about total available market, I'll tell you how we think about it. We look out and start with where do we see differentiated clinical value by procedure given what we can bring, and try to get an estimate of what segment or population of our customer base that can make a positive impact. We start conservatively. What tends to happen over time as we get into those, history has been that as we get clinical data and our customers use our products
We get a better, clearer view of TAM. Often, the TAM has increased. Not always. Some TAMs have decreased, but mostly they've increased. That's how we look at it. SP is clearly an opportunity for us to explore some procedures and patient populations that we have not done a lot in. That, I think, is why we're excited about it. Flex, I think opens a new set of opportunities for us. That's why we have done the investments. I think flexible technologies we're pursuing in the pulmonology space and the thoracic cavity, and we'll be focused on that for the next few years. As you know, we're really excited about platform ideas, things that have generic capability that can be broadened over time. We think flex robotics, diagnostics, and other interventions can do that as well.
We don't have a crystal ball as to those TAMs, and we're not ready yet to describe how big we think they can be, in part because our estimates are large ranges. Could be quite a lot of variability. We invest in them because we think they bring the real opportunity for outcome improvements in the hands of our customers, decreases in variability across the customer base, and as a result, an opportunity to grow the footprint of Intuitive going forward.
Fair enough. Thank you very much.
We do have a question from the line of David Lewis with Morgan Stanley. Please go ahead.
Good afternoon. A few quick questions from me. First, Gary, just coming back to the pipeline. Just on SP, is there a chance we get additional label approvals or submissions for head, neck, and colorectal this year on SP? Is second half of the year a decent timeframe to think about the 40-millimeter stapler approval?
Yeah. I think you meant 60-millimeter stapler. On the SP front, not ready to call timing on labeling additional indications. We'll pursue them with FDA over time. Depends a lot on what kind of data requirements we have and how that conversation goes. We're focused right now on the first one. In terms of clinical capability and customer feedback, we're feeling quite positive, I think the conversation with FDA should be pretty direct and grounded. Predicting the timeline, we're not ready to do yet at this time. On the 60 millimeter, that's a set of products that we have gone back and forth over the years with approvals. I don't think it's wildly different in terms of what we can expect, I think historical timelines for approvals for us are probably good predictors of what happens on the 60 millimeter.
I'm hopeful that we'll see it this year.
Okay. Just a couple more from me, Gary. Just one on spending. I think you're wisely investing away some of the tax benefit, but year-over-year, it's probably $150 million of incremental OpEx and probably $50 million more than we expected for 2018. If you could just sort of give us a sense of where some of the key investment dollars are going here in 2018. Then you mentioned this last quarter, but not this quarter. In terms of hiring the management team for the China JV-
Yeah.
Where are you on CEO, CFO, and what are their near-term priorities?
Great.
Thanks so much.
Yep. Fair question. On the investment side, as the business has strengthened over the last couple of years, we've increased our investments, I think rationally. They have been focused on a couple of things. One has been building depth in OUS markets. Our market presence and penetration in places like Japan and China and Germany, France, UK, and so on, are less than they are in the U.S. We think there is real opportunity for value creation in those markets. We want to make sure that we're not under-investing there relative to the opportunity. That's one segment. The next segment is, I really believe computer-assisted surgery, I think, has moved from an interesting part of minimally invasive surgery department to a kind of an essential part of the portfolio.
As that happens, I think more and more opportunities, competitors, and interest is being generated, and we want to make sure that Intuitive is investing for the long term. I think you all will hold us to the quality of those investments. Mostly, the challenge here has not been identifying opportunity. It's been making sure that if we invest in something, that we have the skill and capability to deliver it with excellence. We've been investing behind things that we think are good opportunities, and I think over time, the wisdom of those decisions will play out. That's kind of mark two. The last thing for us has been as the business has accelerated, we see opportunities for taking advantage of scale and efficiency, and we think that will serve the company well and our customer base well in the future.
As volumes go up, we can convert some capital investments into operating efficiency. You've seen us doing that, and I think that allows us to share with the customer some of those efficiencies. It drives better quality performance in our products. We think that's important as well. As we've seen strengthening, we've loosened some of those dollars, and I have to thank our operations team who've done a beautiful job investing them wisely. Marshall, why don't you take the JV and China question and I'll fill in behind?
Sure. In China, we have hired a CEO. We actually have also hired a CFO and a few other key members of the management team. Right now, they're focused on building out that management team and getting prepared for eventual launch of the business itself. The gating factor there is we're still working on the development of the catheter-based product here in the United States, and as that's completed, then elements of it and the business will start to be handed over to the JV.
The early performance of that team as they've entered our organization is encouraging. The human capital that they're bringing to the board looks pretty strong, so that has been a positive step for us in 2017.
Thanks so much.
We do have a question from the line of Tycho Peterson with JPMorgan. Please go ahead.
Hey, thanks. I guess first question on Japan. I know you don't want to comment on reimbursement levels at this point. It's a bit of a waiting game here, if we think about the 12 procedures that you got approval for, are there ones you want to call out that may be more exciting than others? Maybe could you talk about what percentage of those are done open versus lap across the 12 that have been approved?
Well, it's hard to characterize which ones we're most excited about when you don't know what reimbursements are going to be. You've seen the list, and I think you can size yourself what you think the market opportunity might be. Again, caution you that until reimbursements are announced, we're really not going to know. As Calvin said, there's also an element of adoption that will take place in terms of building out the sales force, building training capabilities, and so forth. There's also, as I said in my script, there's the alternate surgical approaches that may be used that you also have to deal with in adoption. I think once we understand reimbursement and we start to dig into it a little bit more after April 1st is when we'll know that. Maybe we can start to talk a little bit more about the specific procedures.
For me, just looking at the clinical side, I think there are a few things that are pretty exciting in the underlying dynamic and conversations that surgical societies have been having. First, Marshall had mentioned that laparoscopy is fairly penetrated in some of the markets in Japan. Laparoscopic surgeons are quite capable and skilled in that market, yet we continue to have quite strong interest in the use of our technologies there, and I think that's a positive development for us. It indicates that they're looking for clinical improvements and tool improvements over time. Things like gastrectomy, I think, are interesting for us. Hard for us to predict exactly what will happen. It's a highly penetrated laparoscopic procedure with very skilled surgeons in Japan, yet the interest is quite high, and that was one of the things that was studied pretty deeply.
I personally am excited to see how that unfolds over time. It will change it, as to Bob Hopkins' earlier question, how do you think about TAM? Japan is a great example of thinking through how do you do these TAM calculations? We'll see what the mix is with regard to laparoscopy versus robotics, but I'm excited to see how that unfolds. There are thoracic opportunities in the reimbursement as well and other things, gyn oncology. I think there are several things in there that in the mid to long term, I think will be really exciting for us in Japan. I think the Japanese surgical societies and Japanese surgeons are thoughtful and deep, and that'll be a great market to serve. The one caution you've heard us say several times is that it's more than reimbursement.
We have to have the technology training pathways and resources in place. The proctoring networks will be built over time. Our sales team has to get deep with our customer, the near term, there's some hard work and sleeve rolling to go do. That would not diminish my enthusiasm for the long term.
Okay, that's helpful. A question on older systems, kind of two parts here. One, you had a big OUS trade-in number. Was that just a function of the end of the X trade-in program? You're still selling a number of Si systems. I think it was 20 this quarter. Why are customers opting for that versus the X?
Yeah. To answer the last one first. For Si product, there are countries where we do not yet have regulatory approval for X and therefore, we're still selling Sis. There's also some customers have Sis already, and they don't want yet to move into a world where they have two sets of inventory and two sets of training protocol and so forth, so they would rather step into an Si. Then there are some countries where reimbursements are not so high, and they're looking for the cheapest product they can get, and an Si refurb fits that bill. You probably will see the number of Sis we sell decline over time going forward as we get regulatory approvals and we're able to move Xs.
Yeah, on the system retirement side, I think there were 21 total, 18 retired in the field plus three that were lease returns. It's been higher than we've been running, but it's really an expected part of our business cycle. As you know, when a customer elects to stop using a particular system, they're either going to trade it in.
Purchase a new system or just retire it out there in the field. Most of them end up being traded in, but some will end up being retired in the field, and we saw that. In Q4, we were able to confirm that there were 18 of these over 4,400 systems in the field, mostly older models that were no longer being used. We just removed them from our installed base count.
Yeah. I think you were also asking about Europe and the trade-ins in Europe. Is that correct?
Yeah.
Yeah. Trade-ins in Europe, even despite what I said about some customers don't want to enter into a world where they have two sets of inventory, there are those customers that want to standardize on the fourth-generation product. There's also a larger install base of S's and Sis in Europe than in terms of mix relative to, let's say, the U.S. We did see a number of customers in Europe trade out their Sis for X product, so to get into the fourth-generation product and have access then to the latest instrumentation.
The last one, thinking about the mature procedures, in particular dVP in the U.S., anything in 2018 that would change the trajectory relative to what you saw in 2017? I think you kind of mentioned you're back to kind of the market growth rate there. Just curious, I think there's been this expectation that it would decelerate a little bit for a while. Curious as to your thoughts.
Yeah. The results in 2017 exceeded our expectation. Urology was up 8% for the year, dVP is a big piece of that. As kind of the standard for the surgical treatment of prostate cancer, we think that we'd be moving with the overall incidence rate, which is more like low single digits. Our expectation within our guidance range at the low end and the high end is some moderation in the U.S. on prostatectomies in 2018.
Okay. Thank you.
We do have a question from the line of Larry Biegelsen with Wells Fargo. Please go ahead.
Good afternoon. Thanks for taking the questions, guys. One on China, one on the Flex catheter, and just on the tax rate as well. On the Chinese quota, where are you guys in the process there? Do you have any visibility? Is it too late at this point to impact 2018? On the Flex catheter, Gary, on the last call, you sounded maybe optimistic that the CHEST data would be enough for FDA clearance in the U.S. Do you have confirmation of that at this point or any clarification? Just lastly, Marshall, on the tax rate, I thought it would be a little bit lower than 20%-22%. Is there some conservatism there given the uncertainty, or is there something else that we maybe didn't factor into some of the estimates we had? Thanks for taking the questions, guys.
Thanks, Larry. Why don't you take that first one, Marshall? There's no new news on the quota. We sit here waiting, as do you, for news as to what the quota will be. On China, we don't have any indication that is either, A, Intuitive specific or something that we should be foundationally worried about. We're not looking at it and thinking something's wrong here or there's an Intuitive specific indication. Nothing looks like that. You asked the question, is it too late to impact 2018? I don't think so yet. Marshall, looking at you, I don't know how you feel about it. It's hard to know how long the tender process will take at the hospitals. Last time we got a quota approved, a quota was approved in 2013. We didn't see many of the systems sold until the end of 2015.
I don't know whether that same timeline will apply here. Moving to the Flex question. No change in my opinion about data requirements either way. I wouldn't read anything in my comments last time or this time that would indicate a change. Go to tax. The tax rate, the range that Calvin gave is our best estimate. You said that you thought it would have been lower. Clearly, a greater portion of our revenue is still generated in the United States, so more at the higher end. There's the rate itself, the 21%. There are other elements of the Tax Act that add additional taxation on top of that. We've given you the range that we think is the best estimate of what it is. I wouldn't call it conservative.
Thanks for taking the questions, guys.
Thanks, Larry.
We do have a question from the line of Amit Hazan with Citi. Please go ahead.
Thanks. Hey, good afternoon. Let me start with gross margin guidance. In the last two years, you've kind of been nearing that 72% range. FX is now kind of in your favor. You had a pretty big capital year last year that's lower margin. You're kind of implying that might not repeat again in 2018, which is understandable. Seems like very little revenues from new products like the SP this year as you're talking about how we should think about that ramp. Why shouldn't that gross margin number, at the very least, stay consistent with 2017, if not go up a bit?
Yeah, I think like we said in the prepared comments, Amit, the primary driver there is going to be impact of new products. Yeah, we are going to do a phased launch of SP, assuming we get clearance there in 60 millimeter like we talked about. You have the direct margin on the products, but there's investments we make in the lines and the teams and the kind of the structure to make these things that kind of run through on the cost line. A lot of that runs ahead of the higher revenue amounts.
Just a follow-up on the U.S. trade-ins. I'm kind of looking at the year, and maybe a little bit surprised how, I think trade-ins ended the year in the U.S. market actually down 50 units year-over-year, below even 2016 levels. I realize that's actually a positive for the install base and for procedures. In terms of just thinking about the replacement opportunity, given an aging install base in the U.S., how do we best think about the next couple of years for trade-ins?
Yeah. It's hard to estimate when the customers will get to where they want to either standardize on fourth-generation product or avail themselves to latest generation. The Si drives a substantial amount of our procedures. It's a very capable system. In fact, even in situations where customers have suggested that they want to do a trade-in, at the end of the day, they're keeping the Si for either an outpatient care, meaning a point other than the surgery center, or they decide that they've just got volume such that they want to keep it. I don't know how to predict what the trade-in cycle will do over the next couple of years.
Directionally, in terms of our intent, we think Gen4 is quite strong. We think X is a good product, and we think we can deliver X to the install base in attractive economic packages. That's an opportunity for us. It's just really a question I think directionally, we know where it's headed. I think the question is just how long it takes. We want to support our customers and their needs, but I think we have a good offer for them.
Just last one, maybe I heard you wrong, just on imaging hardware for this year, just how much more you can tell us on what to expect in terms of timing of new products, if it's possible that they'd be introduced in 2018, like augmented reality, et cetera, and what we might expect there in terms of potentiality.
Yeah, fair question. When we think about imaging, there's 3 buckets that we think about in investments we make. There's the hardware endoscope side, the sensors, the chips, the optics, the package. We have been investing in that and routinely improving those things, sometimes in big steps, sometimes in small steps. Just as you would imagine, each release of a cellphone has better camera systems. We follow a similar idea, that's been powerful. Those compound effects of improvements are pretty impressive. Second thing is image processing software. The algorithms themselves to shape the image have also been improving over time, also we can release in patches and updates. Then there's the contrast agents and molecules. We work all of them, we often talk about molecules that are kind of the big thing to see. They're long-term investments.
I was reminding everybody here, there are other things going on, too, that the hardware and the underlying software is good. Augmented reality or mixed reality, the idea that you can take graphic images, manage them and get them in, we're making nice progress there. I don't expect material revenue in the year, but I do think that we'll start getting increased customer feedback over the year. As we get closer to customer, we'll inform you more of where we are.
Appreciate it. Thank you.
We do have a question from the line of Isaac Ro with Goldman Sachs. Please go ahead.
Good afternoon, guys. Thanks. 2 questions on Asia, one on China. Just curious what you guys are doing to try and drive penetration while we wait for the quota. Are you better off waiting for the government to give official order? Are there other avenues that you're pursuing to try and drive access? Secondly, on Japan, just appreciate all the comments you made earlier, but I'm wondering how we should think about market development in that region as you get new applications. Are there a couple obvious ways in which physician training and so forth need to be different, and how we should think about your process there? Thank you.
For China, we have a number of systems, 38 systems I think it is, installed at the public hospitals that were subject to the quota. Our distributor is driving clinical adoption there, training surgeons and moving it up. That's why you've heard us talk about increased utilization of those systems and increased number of procedures. The systems that are not subject to the quota really are those in military hospitals in Hong Kong. We actually sold 3 systems this quarter. That's not nearly the market of the public hospitals, but nonetheless, we're making progress in those markets and continue to try to drive expansion.
We think demand from Chinese surgeons and Chinese hospitals is very high, education and engagement is something that we can continue to do. I'll answer the Japan question, operator, this will be our last question after that answer. With regard to Japan, I like the quote, "History doesn't repeat, but it does rhyme." I think about what we need to do in Japan in terms of market development. Our team in Japan is quite capable. They are engaged deeply in communication with surgical societies around what training pathways look like, what educational and coursework ought to look like, things like fellowship programs and so on. I don't think the work is a mystery. It does take time and education of our own team and education of the market. I think we have a senior leader in our general manager in Japan.
I think this is a team that's capable. We will give them time to make progress here. I think they have a playbook they can work down. While it's not identical to the playbook that we used in the U.S. or the ones that we use in Germany, the main elements of engagement are present. As we conclude this call, that was our last question. As we've said previously, while we focus on financial metrics such as revenues and profits and cash flow during these conference calls, our organizational focus remains on increasing value by enabling surgeons to improve surgical outcomes and reduce surgical trauma. We have built our company to take surgery beyond the limits of the human hand, I assure you that we remain committed to driving the vital few things that truly make a difference. This concludes today's call.
I thank you for your participation and support on this extraordinary journey to improve surgery, we look forward to talking to you again in three months.
Ladies and gentlemen, that does conclude your conference for today. Thank you for your participation and for using the AT&T Executive Teleconference Service. You may now disconnect.