Intuitive Surgical Inc. (NASDAQ: ISRG) Q4 2021 earnings call dated Jan. 20, 2022
Corporate Participants:
Brian King — Head, Investor Relations
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Jamie Samath — Chief Financial Officer
Analysts:
Larry Biegelsen — Wells Fargo Securities — Analyst
Tycho Peterson — JPMorgan — Analyst
Amit Hazan — Goldman Sachs — Analyst
Rick Wise — Stifel — Analyst
Matt Taylor — UBS — Analyst
Presentation:
Operator
Ladies and gentlemen, thank you for standing by and welcome to the Intuitive Q4 2021 Earnings Release Call. [Operator Instructions] As a reminder, today’s call is being recorded.
Now, I’d turn the conference over to our host, Brian King, Head of Investor Relations for Intuitive Surgical. Please go ahead.
Brian King — Head, Investor Relations
Thank you. So good afternoon and welcome to Intuitive’s fourth quarter earnings conference call. With me today, we have Gary Guthart, our CEO; and Jamie Samath, our CFO.
Before we begin, I would 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 our Securities and Exchange Commission filings, including our most recent Form 10-K filed on February 10, 2021 and Form 10-Q filed on October 20, 2021. Our SEC filings can be found through our website or at the SEC’s website. 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 intuitive.com on the Latest Events section under our Investor Relations page. 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, Jamie will provide a review of our financial results and I will discuss procedure and clinical highlights and provide our financial outlook for 2022. And finally, we will host a question-and-answer session.
And with that, I’ll turn it over to Gary.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Thank you for joining us today. 2021 required agility as we drove through significant headwinds to support customers and manage our supply chain. Our teams performed well, helping customers return to surgery when COVID allowed them and maintaining the integrity of our supply chain and workforce. Given our recent press release updating procedures, capital placements and revenues, I’ll be brief in describing our full year 2021 results and spend a little more time outlining our plans for 2022 and beyond.
Putting 2021 in context, demand for our robotically-assisted interventions has been resilient during COVID. While these interventions get delayed during COVID peaks, they return as COVID wanes and that is encouraging. Pandemic stresses on healthcare systems, emphasize the need for the kind of high quality, minimally-invasive interventions our products enable. MIS procedures allow greater use of ambulatory surgery, free up resources in ORs relative to other approaches and often enable faster patient return to home and overall recovery.
In 2021, da Vinci procedures grew 28% compared to full year 2020, reflecting a partial recovery in surgery after the first wave of the pandemic. Over the two-year period 2020 and 2021, the compound annual growth rate in procedures was 14%. Capital installs were healthy in 2021, with our team placing 1,347 da Vinci and 93 Ion systems in the year, driving da Vinci placement growth of 44% over 2020 and had a CAGR of 10% over the past two years.
With a two-year CAGR in procedures of 14% and installed base growth of 10% over the same period, utilization of installed systems continue to climb through the pandemic. We think this is good for our customers and good for us. Jamie will give regional capital trends and Brian will give detailed procedure dynamics later in the call.
The past two years have stressed more than health systems. Our ability to attract, develop and retain outstanding staff remains a key focus for us. Our team has performed well, supporting our customers and each other. In the year, we added approximately 1,700 employees to our team with net headcount growth of approximately 180 in R&D, 920 in operations and 340 in our commercial force. Of the 1,700 net additions, 700 were outside of the United States.
Looking out over the next decade, we believe that the method we have developed to identify clinical need, then design a technology-enabled ecosystem for improving the quadruple aim, then deliver and train customers on this ecosystem can positively impact a broad set of minimally-invasive interventions. The opportunity and challenge for Intuitive is to evolve our ecosystem to support our customers and ourselves at scale and to choose procedural opportunities and platform architectures that made sense.
Turning to investments in the mid-term, our priority for use of our capital is to reinvest in the business, to develop new opportunities that improve the quadruple aim and to strengthen our operating capabilities at global scale. We are focused on driving a vital set of initiatives, and I’d like to describe the dynamics for you in a little more detail.
In multiport, we believe our Gen 4 architecture is outstanding. And we’ve been adding capability to this product line since launch, including significant expansion and upgrades to energy and stapling product lines, improved endoscopic imaging, the introduction of da Vinci X, the introduction of extended use instruments, training technologies and, finally, the introduction of new and upgraded connectivity and data management tools.
Given the precision, robustness and overall performance of our Generation 4 robotics architecture, we will continue to innovate on this platform, bringing additional value to those customers who have standardized on Generation 4 fleets. We are also investing a new core capabilities for our multiport systems, both Generation 4 and beyond that we’ll describe as they get closer to market. You should expect continued innovation from us here.
Turning to Ion, our first indication addresses a large unmet need in lung cancer biopsy and our focus is fully enabling our production capability and customer ecosystem for this indication. There is strong demand for lung biopsy and we are working to expand manufacturing capacity of all processes for greater quality and lower costs at scale and run trials and address regulatory requirements that enable global expansion. Over time, we plan for a total Ion program profitability to approach that of our corporate average as we execute against our volume, design and process improvement goals. We are pursuing additional applications for Ion and we’ll describe them as we get closer to market.
For our single port system, da Vinci SP has the opportunity to change the standard of care in two different types of soft tissue surgery, those that require the extraction of tissue that can be done through a small single port and those procedures that benefit from narrow entry into the body as a whole. Where Ion at its current stage of launch has a single indication that represents large patient population, SP’s opportunity is the aggregation of several mid-size indications.
For example, SP use in trans-oral robotic surgery is growing steadily in the US. To broaden SP’s applicability in the US and other markets, we’re undertaking clinical trials to support regulatory review. We believe that SP will serve several additional surgical specialties, which will allow our customers and us to leverage capital investments in the program. Like Ion, we plan for SP platform profitability to approach that of historical platforms over time and we’re encouraged by recent progress.
Our customer digital efforts now represent roughly 5% of our total operating expenses and drive the business in four ways. First, the use of data and digital tools by customers to analyze their operations helps improve outcomes, reduce costs and increase customer satisfaction and retention. Second, digital and internal investments can decrease our cost to serving our customer. Third, some of our digital tools generate revenue themselves. And finally, use of data and analytics internally can help our teams make better decisions. Because digital and data tools expand our platforms and are used externally and internally, we do not account for them using the same financial models as our platforms, nor do we break them out as standalone financial engines. That said, we do evaluate digital and data projects against internal strategic and return analysis.
Over the past five years, the annual number of instruments we produce has grown roughly 200% and the annual number of systems we produce has more than doubled. The number of customer professionals trained annually has nearly doubled and our engineering staff has nearly tripled. Our product volume growth has also allowed us to in-source some of our high volume accessories, while investing in automation. This has a three-fold benefit, improving supply chain robustness, improving manufacturing quality and lowering unit costs.
As our training, R&D, and manufacturing efforts move to scale, we’re investing in infrastructure, factory builds, training center expansion and automation. These infrastructure investments are lumpy and our current growth cycle requires building capacity. These projects have been planned over the past couple of years and we’ll start amortizing first moderately in 2022, and more substantially in 2023 and ’24, then normalizing over the next few years.
For example, over the next four years, we’ll be growing and consolidating facilities for operations, R&D and customer training space in Atlanta, doubling our Mexicali manufacturing footprint, doubling our R&D design space and operation space at our California headquarters and, finally, consolidating and growing our commercial training operations and R&D space in Freiburg, Germany.
In summary, we’ll build on our Generation 4 capabilities in multiport, while innovating in clinical utility for multiport surgery broadly. We’ll continue to bring our flexible endoscopy platform Ion to scale and drive capacity, quality and cost improvements, while seeking to broaden access to new markets.
In SP, we expect to expand indications in regional markets, while driving manufacturing, quality and scale. We will invest in regional training, R&D and manufacturing centers globally to support the growth of the business and pursue opportunities for operating leverage, given volume, some of which we’ll share with customers to catalyze elastic markets. Finally, we will continue to advance our digital efforts to enable fast, accurate and actionable decisions with our customers and for our company.
Lastly, for 2022 particularly, we’re focused on the following: first, outstanding customer support in the face of continued pandemic disruption; second, execution of a robotic and digital platform expansion in pursuit of new indications and new markets; third, general surgery growth in the United States; and finally, diversified growth outside the US beyond urology.
As we turn to our financial report, I’d like to formally thank Marshall Mohr, our outgoing CFO and new Head of Global Business Services, for his outstanding stewardship over the past 15 years, and turn the time over to our incoming CFO, Jamie Samath, who’ll take you through financial matters in greater detail.
Jamie Samath — Chief Financial Officer
Good afternoon. I would describe the highlights of our performance on a non-GAAP or pro forma basis. I will also summarize our GAAP performance later in my prepared remarks. Reconciliation between our pro forma and GAAP results is posted on our website. Q4 and 2021 revenue and procedures are in line with our preliminary press release of January 12.
Before I dive into our Q4 results, let me start with the summary of our full year 2021 performance. Given the significant impact of COVID, we believe it’s appropriate to review our 2021 results on both a year-over-year and a two-year compound annual growth rate basis. Procedures increased by 28% as compared to 2020 and increased by approximately 14% using a two-year CAGR. We placed 1,347 systems of customers during the year, an increase of 44% as compared to 2020 and up 10% using a two-year CAGR. As a result of this procedure and system placement performance, 2021 revenue increased by 31% year-over-year and increased by 13% using a two-year CAGR.
Key business metrics for the fourth quarter were as follows. Fourth quarter procedures increased approximately 19% compared with the fourth quarter of 2020 and increased approximately 13% using a two-year CAGR. During the quarter, procedures continued to recover in October and November from the impact of the Delta variant in Q3. However, in December, procedures were adversely impacted by the increase in hospitalizations in the US and parts of Europe as the Omicron variant spread rapidly. This trend has worsened so far into January.
Fourth quarter system placements of 385 increased 18% from the 326 systems placed last year. As a result, net of trade-ins and retirements, we expanded our installed base of da Vinci systems over the last year by 12%. On a two-year CAGR, our installed base is up 10%. Utilization of clinical systems in the field measured by procedures per system increased approximately 7% compared to last year and increased approximately 3% using a two-year CAGR.
During the quarter, the supply chain environment became more challenging and remains highly dynamic. Our supply chain teams continue to work tirelessly with our supply chain partners to fulfill customer demand. In Q4, we experienced minor constraints on our ability to meet customer demand. For example, we had some limitations on supply of skilled simulators. While these constraints were relatively minor and were immaterial to our overall Q4 financial results, they highlight the risk of potential significant disruption to our manufacturing operations due to the current supply chain challenges.
US procedures grew approximately 16% over Q4 2020 with relative strength in bariatrics, cholecystectomy and hernia repair. The December impact of the current wave of COVID on US procedures varied by region with a greater impact in the Northeast and Midwest. Benign procedures such as benign hysterectomy experienced a more significant impact in December, reflecting the deferability of certain elective surgeries.
In Europe, the impact of COVID on procedures in December was most notable in France and Italy. Despite the fact that hospitals are generally better equipped to handle COVID patients today compared to the outset of the pandemic, COVID-19 resurgences like those currently being experienced in the US and parts of Europe have challenged hospital resources and have negatively impacted da Vinci procedures.
In the US, high COVID-related hospitalization rates have been exacerbated by staffing shortages. According to data reported by the Department of Health and Human Services, the proportion of hospitals reporting at critical staffing shortage doubled between July and December. In addition, delays in diagnosis and treatment of underlying conditions have and will also negatively impact da Vinci procedures.
Q4 procedures in Asia were not significantly impacted by a resurgence in COVID. We saw strong procedure growth across multiple specialties in China, Korea and Japan. While it is difficult to predict how long the current wave of COVID will last or the extent to which it will impact additional geographies, we expect that da Vinci procedures will be significantly adversely impacted in Q1. Brian will provide additional procedure commentary later in this call.
Overall system placement results in Q4 was solid with US placements of 235 up 20% from 196 in Q4 of 2020. System placements at greenfield customers were strong, up approximately 45% as compared to Q4 of 2020, driven by US IDNs and new customers in OUS markets. Outside the US, we placed 150 systems in the fourth quarter compared with 130 in the fourth quarter 2020. Current quarter system placements included 63 into Europe, 37 into Japan and 14 into China compared with 54 into Europe, 22 into Japan and 13 into China in the fourth quarter of 2020.
Capital strength in Japan was driven primarily by new customers in the private sector. As of the end of 2021, there were 63 systems remaining under the current quarter in China, which may be accessible to competitors should they receive local regulatory clearance. Globally, trade-in transactions represented 30% of placements in the quarter, down from 40% last quarter and 49% for 2020. The remaining installed base of Xi systems in the US is approximately 343 systems.
We expect the volume of trade-ins to be significantly lower in 2022 as compared to 2021. Macroeconomic conditions created by COVID, including supply chain constraints and staffing shortages are challenging and could impact hospital capital spending. In addition, as competition progresses in various markets, we will likely experience longer selling cycles and price pressure.
Additional revenue statistics and trends are as follows: total fourth quarter revenue was $1.55 billion, an increase of 17% from last year. Leasing represented 37% of Q4 placements compared with 41% last quarter and flat to Q4 of 2020. The lower leasing mix in Q4 relative to last quarter reflected higher multi-system placements for the couple of IDNs who preferred to purchase systems. While leasing will fluctuate from quarter-to-quarter, we continue to expect that the proportion of placements under operating leases will continue to increase over time.
Fourth quarter system average selling prices were $1.45 million similar to $1.43 million last year and lower than $1.57 million last quarter. The sequential decline was primarily driven by a higher mix of bulk buy transactions with large customers. We recognized $26 million of lease buyout revenue in the fourth quarter compared with $25 million last quarter and $14 million last year. Lease buyout revenue has varied significantly quarter to quarter and will likely continue to do so.
Instrument and accessory revenue per procedure was approximately $1,940 per procedure compared with $1,900 per procedure in the third quarter of 2021 and down 6% from $2,060 realized in the fourth quarter of last year. The year-over-year decrease primarily reflects the benefit of stocking orders in Q4 of 2020 associated with the launch of our extended use instruments program in the US and Europe. The sequential increase primarily reflects continued growth of our advanced instrument portfolio. As we highlighted recently, revenue for our advanced instrument portfolio has grown over a five-year period at a compound annual growth rate of 35% and we are starting to see early and accelerating adoption in OUS markets.
10 of the systems placed in the fourth quarter were SP systems, including three systems placed at customers in Korea. Our installed base of SP Systems is now 99. During the quarter, we further developed our SP ecosystem, receiving 510(k) clearance for our Firefly imaging technology. We also received 510(k) clearance for enhancements to our SP instruments, including an extension of life to six of our eight instruments. Growth of the SP platform will continue to be gated by additional clinical indications and clearances in markets beyond the US and Korea.
We placed 31 Ion systems in the quarter, bringing the installed base to 129 systems. Looking at the 93 Ion systems placed in 2021, 54% of those systems were placed under operating lease arrangements. For reference, the list price of our Ion system is $600,00 with ASPs generally a little below that level. As a reminder, Ion system placements and procedures are excluded from our overall system and procedure counts. The entirety of our Ion installed base is with the existing da Vinci customers, the majority of which have large pulmonary and thoracic departments. Our Ion platform is also installed at the majority of accounts that have an IP fellowship program. We continue to be encouraged by customer feedback and look forward to the completion of our next major milestone, the full results from the precise study, which is expected in the second half of 2022.
Moving on to gross margin and operating expenses. Pro forma gross margin for the fourth quarter of 2021 was 70.1% compared with 69.7% for the fourth quarter of 2020 and 71.3% last quarter. The fourth quarter of 2020 included higher period costs associated with lower production and higher excess and obsolete inventory charges. Pro forma gross margin was lower than last quarter, primarily as a result of manufacturing inefficiencies and higher logistics costs associated with the supply chain environment, lower system ASPs and a higher mix of systems revenue.
Pro forma operating expenses increased 27% compared with the fourth quarter of 2020. The fourth quarter of 2021 included a $30 million contribution to the Intuitive Foundation compared with a $25 million contribution in the fourth quarter of 2020. The increase in fourth quarter operating expenses from a year ago reflected an increase in headcount, increased variable compensation, and higher travel costs. We finished 2021 with almost 9,800 employees, an increase of 21% from the end of 2020. We believe the opportunity in robotic-assisted interventions to be significant and are planning to increase our investment significantly in 2022. We are at the early stages of our newer platforms SP and Ion and we will continue to invest in our digital and data capabilities. Brian will provide operating expense guidance later in this call.
As Gary described, we are also investing in our infrastructure to support our growth objectives and facilitate our ability to scale. In 2022, we expect a significant increase in capital expenditures in the range of $700 million to $1 billion of capital investment for the year. A significant portion of this investment involves construction of facilities to provide incremental space for growth, to consolidate operations to enhance efficiency, and to replace leased spaces with owned spaces. These capital investments also expand our OUS footprint in support of opportunities for growth in key international markets where da Vinci procedures are in earlier stages of adoption. These are multi-year investments.
Our pro forma effective tax rate for the fourth quarter was 19.5%, lower than our expectation primarily due to a favorable US-OUS income mix. We expect that our pro forma tax rate will increase in 2022 due to a previous change in US tax law that became effective on January 1, 2022. Brian will provide details later in this call. Our fourth quarter 2021 pro forma net income was $477 million or $1.30 per share compared with $434 million or $1.19 per share for the fourth quarter of 2020.
I will now summarize our GAAP results. GAAP net income was $381 million or $1.04 per share for the fourth quarter of 2021 compared with GAAP net income of $365 million or $1.01 per share for the fourth quarter of 2020. The adjustments between pro forma and GAAP net income are outlined and quantified on our website and include excess tax benefits associated with employee stock awards, employee stock-based compensation, amortization of intangibles and IP charges, acquisition-related items and legal settlements.
We ended the year with cash and investments of $8.6 billion compared with $6.9 billion at December 31, 2020. The increase in cash in the fourth quarter primarily reflected cash generated from operations. We did not repurchase any shares during the quarter.
And with that, I would like to turn it over to Brian who will discuss clinical highlights and provide our outlook for 2022.
Brian King — Head, Investor Relations
Thank you, Jamie. Overall procedure growth for the full year 2021 was approximately 28% as compared to 1% in 2020 and increased 14% using a two-year compound annual growth rate. Overall procedure growth was comprised of 27% growth in the US and 32% growth in OUS markets. In the US, fourth quarter growth was driven by growth in procedures within general surgery. Bariatrics, cholecystectomy, and hernia repair were the largest contributors to procedure growth within the quarter.
Fourth quarter OUS procedure volume grew approximately 28% compared with 11% for the fourth quarter of 2020 and 30% last quarter. In 2021, non-urology specialties approached half of all OUS procedures and grew faster than urologic procedures. More specifically, at a region and country level, in China, Q4 procedures also had broad-based growth in urology, thoracic, general surgery and gynecology. General surgery, thoracic and gynecology procedures grew faster than urology and, combined, made up more than total urology procedures in the fourth quarter.
In Japan, da Vinci prostatectomy has emerged as standard of care for the surgical treatment of prostate cancer. We’ve also gained significant market share in other urologic procedures, including partial nephrectomy and cystectomy. The robust growth that we continue to see in Japan is now attributable to growth in general surgery, thoracic and gynecology procedures that were granted reimbursement status subsequent to urologic procedures.
In Europe, procedure performance varied by country. But in procedures outside of urology, growth was driven by colorectal, hysterectomy for cancer and thoracic procedures.
Now, turning to the clinical side of our business, I’ll highlight two recently published studies that we deem to be notable. However to gain a more complete understanding of the body of evidence, we encourage all stakeholders to thoroughly review the extensive detail of scientific studies that have been published over the years.
During the quarter, researchers from the University Hospital of Southern Jutland and the University of Southern Denmark published results from a systematic review and meta-analysis evaluating the short-term outcomes of robotic-assisted and laparoscopic colon surgery for patients with cancer. This analysis included 20 studies from 2005 to 2020 describing comparing outcomes from over 13,000 subjects with over 1,500 robotic-assisted procedures and over 12,000 laparoscopic procedures.
Between the two groups, a significant difference favoring the robotic-assisted approach demonstrated a 46% lower risk of anastomotic leakage. In addition, robotic-assisted colon surgery showed a 69% lower risk of conversion to open when compared to the laparoscopic approach, while also demonstrating a 15% reduction in the overall complication rate, favoring the robotic-assisted approach and a seven-hour reduction in time to regular diet.
Interestingly, a subgroup analysis was performed analyzing right-sided hemicolectomies, noting the prevalence of this procedure in the studies analyzed. And with over 850 subjects in the robotic-assisted group and over 3,000 subjects in the laparoscopic group, the robotic-assisted approach was similarly favored with regards to anastomotic leakage, rate of conversion to open and the length of stay. The authors concluded in part, “Robotic-assisted colon surgery showed advantages in colon cancer surgery regarding surgical efficacy and morbidity compared to laparoscopic colon surgery.”
In November of last year, Christopher Seder from Rush University Medical Center in Chicago, published propensity adjusted analysis comparing robotic-assisted and thoracoscopic anatomic lung resection in obese patients. Leveraging data from the Society of Thoracic Surgeons’ general thoracic database, Epithor, a French national database and McMaster University thoracic surgical database, over 8,000 subjects were identified for analysis with over 2,100 robotic-assisted subjects and over 5,900 VATS subjects included.
After propensity score adjustments of the populations, the VATS patients showed a 15% rate of conversion to open compared to only 3% in the robotic cohort, which corresponded to risk of conversion 5 times higher for the VATS approach. In addition, the robotic-assisted group demonstrated a shorter mean length of stay of approximately 0.7 days, 1% lower risk of respiratory failure and were more likely to be discharged home after the procedure. Of note, this analysis is the first propensity adjusted analysis comparing VATS and robotic-assisted anatomic lung resection in obese patients as well as the first pool of contemporary international patient level data.
The authors concluded in part, “Overall, these data suggest that obese patients with early-stage non-small cell lung cancer undergoing minimally-invasive anatomic lung resection with VATS have a higher rate of conversion to thoracotomy when compared to patients undergoing anatomic lung resection with robotic-assisted surgery.”
I will now turn to our financial outlook for 2022. Starting with procedures, as described in our announcement earlier this month, total 2021 da Vinci procedures grew approximately 28% year-over-year and 14% at a two-year compound annual growth rate to roughly 1,594,000 procedures performed worldwide.
During 2022, we anticipate full year procedure growth within a range of 11% to 15%. This range reflects the uncertainty associated with the course of the pandemic. The low end of this range assumes ongoing COVID pressure and hospital staffing shortages, while the high end assumes no significant new surges after the current wave. In addition, this range does not contemplate any material supply chain disruptions throughout the year.
We expect 2022 procedure growth to continue to be driven by US general surgery and procedure growth in OUS markets where we are at earlier stages of adoption. We expect similar seasonal timing of procedures in 2022 as we have experienced in previous years prior to COVID with Q1 being the seasonally weakest quarter as patient deductibles are reset. We expect Omicron to have a significant adverse impact on procedures in the first quarter.
With respect to revenue, as we have mentioned previously, capital sales are ultimately driven by procedure demand, catalyzing hospitals to establish or expand robotic system capacity. Capital sales can vary substantially from period to period based upon many factors, including US healthcare policy, hospital capital spending cycles, reimbursement and government quotas, product cycles, economic cycles and competitive factors.
Within this framework, we’d expect 2022 capital placement seasonality to generally follow historical patterns by quarter, but could also be impacted by hospital staff shortages and the allocation of resources to managing current care. During Q3 and Q4, 40% and 30% respectively of systems placements involve trade-ins of older systems to our da Vinci Xi. As we mentioned last quarter, we expect the volume of trade-ins to be significantly lower in 2022 as compared to 2021.
Turning to gross profit. Our full year 2021 pro forma gross profit margin was 71.2%. In 2022, we expect our pro forma gross profit margin to be within a range of between 69.5% and 70.5% of net revenue. The slightly lower gross profit margin anticipated in 2022 reflects higher fixed costs from investments to drive growth of the business, strengthen our operating capabilities and also reflects the impact of higher supply chain costs. Our actual gross profit margin will vary quarter-to-quarter depending largely on product, regional and trade-in mix and the impact of new product introductions.
Turning to operating expenses. In 2021, our pro forma operating expenses grew 19%. In 2022, we expect pro forma operating expense growth to be between 21% and 27%. The operating expense growth reflects increased investment in R&D for our new product platforms, expanding OUS capabilities and the return of other spending that was previously restricted by COVID.
We expect our non-cash stock compensation expense to range between $510 million to $550 million in 2022 compared to $452 million in 2021. We expect other income, which is comprised mostly of interest income, to total between $45 million and $55 million in 2022.
With regard to income tax, in 2021, our pro forma income tax rate was 22.2%. As we look forward, we estimate our 2022 pro forma tax rate to be between 22% and 24% of pre-tax income, with the increase primarily due to a change in US tax treatment of certain expenditures that was enacted in 2017 but became effective on January 1, 2021.
Lastly, I would like to highlight that our Annual Sustainability Report will be available after this call on our Investor Relations website. In the latest report, we provide an overview of the current state of our sustainability strategy, areas of focus, key actions taken over the past year to develop sustainable solution that meet our customer needs in new ways and our results achieved to-date.
That concludes our prepared comments. We will now open the call to your questions.
Questions and Answers:
Operator
Thank you. [Operator Instructions] Our first question is going to come from the line of Larry Biegelsen from Wells Fargo. Please go ahead.
Larry Biegelsen — Wells Fargo Securities — Analyst
Good afternoon. Thanks for taking the question. Two questions from me. Gary, I wanted to start with a high-level question. You started using this slogan at the point of possibility recently and you’ve talked about being at the point of possibility to build what’s needed next. Can you talk about why you started using this new slogan and what are the needs you’re trying to address? And I had one follow-up.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
I think we have — thanks, Larry. I think we have a broad opportunity as a company here to take the methods that we have designed around identifying clinical need, doing the design and development of tech-enabled ecosystems to address that need and then working with customers to deliver it and train it. And there’s, I think, long-term, a lot of opportunity. As we look out, there is substantial opportunity in existing markets and in new ones to do better for the quad aim. Doing this set — getting that set of ecosystem investments ready is heavy work. It’s a multi-year effort. But we think we’ve shown that it can be done. And I think that’s really what we’re talking about here is the ability to start to impact other opportunities in international markets as we go forward and Ion is such an example.
Larry Biegelsen — Wells Fargo Securities — Analyst
Thanks for that, Gary. And it seems like so far you’ve mitigated potential supply constraints well. How are you trying to mitigate them going forward? And would you describe the situation as getting better or worse and how concerned are you about that? Thanks for taking the questions.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Yeah, I’ll take the top and then I’ll let Jamie take some more. At the very top part, it’s kind of three big buckets. One of them is specific products themselves, semiconductors come to mind. The second bucket is some raw material constraints and the kinds of things we build. And the third is just logistics and motion of materials.
Jamie, I’ll let you fill in that perspective.
Jamie Samath — Chief Financial Officer
Hey, Larry. So, I think we said in our prepared remarks we saw the supply chain environment actually get worse in Q4 and we highlight that we actually had some, as I quoted, minor constraints on our ability to fulfill customer demand. You have a set of metrics there in the supply chain. One example we’ve given is, on-time delivery from our suppliers was less in Q4 as compared to Q3. As you look forward, I’d say that at this point, visibility is still not great. Kind of the best read that we have is that Q1 will be similar as to Q4, but I think we have to wait and see what the impact of Omicron might be on our suppliers and just broadly. So, I think we’re continuing to navigate through it. As I said, our supply chain teams are really still in hand-to-hand combat every day working with our partners.
Larry Biegelsen — Wells Fargo Securities — Analyst
Thanks for taking the questions.
Operator
Our next question then will come from the line of Tycho Peterson from JPMorgan. Please go ahead.
Tycho Peterson — JPMorgan — Analyst
Hey. Good afternoon. Gary, you’ve talked about being at the end of the replacement cycle for a little while now and obviously you’re retiring the S models. I’m curious how we should interpret that comment about being near the end of the replacement cycle. As we think about maybe where you could be headed from an innovation standpoint, is it all about kind of driving down the length of procedures, making procedures easier with less training and expanding into newer indications or maybe just — I’m curious, from a technology standpoint, if you could talk a little bit about at a high level where you’re headed.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Yeah. Let’s talk for a moment about replacement cycles. I think you’re referring to the Si. Jamie had mentioned it in his prepared remarks and Brian had touched on it. I think they were pretty clear and I won’t go through that. I do think that from a business model point of view we don’t think that we need to drive capital upgrades on Intuitive’s calendar to have a healthy business. What we look at is, where can we drive the quadruple aim and how can we effectively do that for our customers. And in that setting, we have been investing in our Gen 4 platform and expansion. I talked about that in my prepared remarks as well. And it’s been great for the customers and for us. That’s not the only thing we’ll do, but it’s an important thing that we do.
You had mentioned a little bit on the technology stack, what are the kinds of things we care about. And a lot of what we are driven by are what kinds of things can we do inside the body in imaging, in informatics that will dramatically change outcomes or the experience of the patients or the care team. And that has — you can see that in the kinds of things that we brought to market. We have fantastic teams. We have things that we’re working on that we have not yet discussed that we think will drive differences in outcomes. So it’s not just working on new indications or just working on ease of use. I think those things are both important, but it’s not limited to that. There are other things that are going on that we think can change the nature of our interaction with tissue and drive outcomes again and raise the bar there once more.
Jamie, anything you’d want to add on the issue of Si replacement cycle?
Jamie Samath — Chief Financial Officer
I would just maybe give you some numbers. In 2021, globally we did about 510 trade-ins. About 80%-ish of those were in the US. So US has been driving those trade-ins. And so, then if you compare that to the remaining installed base of 343, it’s why we provided the commentary that we expect overall trading volume in ’22 to be significantly lower than ’21, just because the remaining installed base is being depleted.
Tycho Peterson — JPMorgan — Analyst
Okay. That’s helpful. And speaking of innovation, can you touch on some of the SP enhancements? You talked about 510 clearance for extension of life for some of the instruments. Can you just clarify exactly what you got through?
Jamie Samath — Chief Financial Officer
Yeah. So we’ve received obviously customer feedback along the way since we launched SP. And some of our customers have asked for greater ability to do extraction. That’s really around the range of motion within the anatomy of our instruments that do extraction and grip strength as you grasp tissue. We’ve had customer feedback that we could improve the grip strength. And so, along with the extension of lives, we responded to customer feedback and improved the instruments accordingly as described.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
We’ve done some other things too. We have, as you know, a dual console that helps with training of the new surgeons and teaching environments. We extended the dual console capability into the SP space recently, we’ve launched and then upgraded some of the accessories that go with SP. So, part of the process, for those of you who have been with us for a while, is continuous innovation. These things don’t end where they start and that’s been true for SP.
Tycho Peterson — JPMorgan — Analyst
Great. One last one just on the headcount. You started the call off highlighting all the additions last year. Should we think about a kind of similar magnitude of increase in ’22?
Jamie Samath — Chief Financial Officer
I think, if you look at the opex increase range that Brian provided, I think you can kind of draw a correlation between how headcount has kind of correlated to spending increase, and I think that’s a relevant starting point for ’22.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
We also gave you a mix in the script of kind of where they’re headed, how much is R&D, how much is operations, commercial and that’s not a bad guide either as to kind of where the mix is going.
Tycho Peterson — JPMorgan — Analyst
Okay. Thank you.
Operator
Our next question then will come from the line of Amit Hazan from Goldman Sachs. Please go ahead.
Amit Hazan — Goldman Sachs — Analyst
Hello. Thanks. Hey, good afternoon. I’ll start with a shorter-term one and then a longer-term one for Gary. Shorter-term, just on the first quarter, just realizing the moving parts and it’s fluid inside of the quarter, but how much help can you give us as to what you’ve seen so far, and how do we model procedures in this environment? You said severely impacted but we have to put a number out there. So I’m curious, how much help you can give us for whether procedures are down at the moment or how much they’re down, that would be terrific. And then also on capital, if you’re seeing anything quite yet in terms of delays in capital spending because of everything going on at hospital level and how we should think about ’22 for capital spending relative to last year. What you feel the environment is like?
Jamie Samath — Chief Financial Officer
Amit, I’ll give you a couple of data points. So, the greatest correlation we’ve seen historically on procedures is rates of hospitalizations. I believe that currently US hospitalizations related to COVID are beyond any of the previous ways. And so, I think you can kind of track how that has progressed so far and what some of the third parties are projecting for the remainder of the quarter. There’s some modeling benefit to doing that. What I would point to is, if you look at pre-COVID, so 2017, ’18, ’19, those — the sequential change between Q4 and Q1 was about even, meaning it was about the same Q1 as Q4, so that’s in a normal quarter. Most of the current wave will be in Q1. The impact of Omicron in Q4 was kind of later in the quarter. And so, I kind of start with a normal quarter would be flat sequentially and then model the rest of Q1 based on just hospitalization rates.
With respect to capital, there’s nothing at this point to call out. I do think that the combination of what’s happening right now with COVID, along with staffing shortages, along with the extent to which the supply chain environment broadly could impact hospitals could make it challenging for hospital capital spending. They may need to manage that more carefully in such an environment, but there is nothing specific that we would call out at this point.
What was the third part of your question, Amit?
Amit Hazan — Goldman Sachs — Analyst
Yeah, that was actually it. I just have a longer-term one for Gary on — just given some of your comments that you made, it just kind of brings up in my mind just to ask you about what your thoughts generally are about a SaaS type model and more specifically to SimNow. We’ve talked to some of your customers over the past year or so. And it seems like some of them are being charged for SimNow software, somewhere around $20,000 a year in the service line. And so, I wanted to see how you would frame that specific opportunity inside of kind of thinking about it with your installed base.
And then, more broadly and more importantly, just to see if you could just talk to this kind of SaaS type of model and whether we’ll be seeing more of these types of offerings from you in the future. Thanks so much.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Sure. On the issue of kind of recurring revenue or service models versus kind of capital single charge. We have taken a posture of being really flexible with what our customer wants. There are some really nice things about as the transition — as the company has transitioned to a recurring model that customers can come to choose when they’re ready to engage with us and it doesn’t require large upfront capital expenditures.
For some things that are inherently services and if you think about simulation, it’s not really about the hardware in the case of simulation, it’s really about access to modules and modules that improve over time and modules that get built to be specific to competency-based training. Subscriptions make a lot of sense because you’re not really trying to sell a piece of hardware, you’re really helping them develop a training program over time. So, we think increasingly as our business in software and analytics and some of the digital tools that we’re bringing come up, then subscriptions may make sense. And to the extent that they align with customers, we’re happy to do it.
I also like the idea of recurring revenue in that it focuses the organization on earning the customers’ business every day that it’s a lot less lumpy for them and it’s a lot less lumpy for us. And if we’re bringing value and helping them achieve their quadruple aim goals, then they’re happy to stay with us in those events. So I would expect that the recurring revenue portion of our business keeps creeping up as a percentage of total revenue over time. So long as customers are aligned to that, that makes sense from their finances point of view, then that’s what we’ll pursue. And to the extent that they’re interested in other models, then we are open-minded.
Amit Hazan — Goldman Sachs — Analyst
Thank you.
Operator
Our next question then will come from the line of Rick Wise from Stifel. Please go ahead.
Rick Wise — Stifel — Analyst
Good afternoon. Hi, Gary. I thought I’d follow-up on a couple of things. You highlighted very specifically for both Ion and da Vinci SP this concept of margins aren’t where they will be and over time you’re going to bring the business to scale. I was wondering if you could expand on that, maybe give us a flavor for where margins are now and how do we think about — is this two years away? Is it five years away? How do we think about the trajectory going forward there?
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Thanks for the question. On the kind of where we’re headed, we look at those architectures and we think based on our experiences understanding our supply chains, understanding what iterations in engineering and manufacturing look like, that both of those platforms should be able to hit historical norms in the future years — and not forever, in future years. That said, in the early innings here, you’re at lower volumes relative to where you’re going to be. You’re also working through some manufacturing process improvements and doing some of the capital investments that you need to do in order to get unit costs down.
I’ll look to Jamie in terms of characterizing kind of roughly where they are. SP is a little more mature product line in our hands in terms of manufacturing. And our GM and her team over there are doing a really nice job, identifying those opportunities and sequentially knocking them down over time, feels really good. Ion is a little earlier and it’s going through a little bit different growth ramp, and so it’s going to have to work its way down that process, although we also feel good about kind of the core architectures that would — that give us some confidence that we can hit those objectives.
Jamie, anything that you would want to add?
Jamie Samath — Chief Financial Officer
Rick, I would split the question kind of into two categories. There’s gross margin and then there’s, let’s call it, the equivalent of operating margin. On a gross margin basis, kind of the actions that we have to take to get both Ion and SP to kind of, let’s call it, target gross margins are well understood. And it’s really about execution over a period of time. A component of that will obviously be building scale, but I think those actions are well defined. They are a multiple-year effort.
On the operating margin side, it’s really what’s revenue in relation to the amounts that we are investing. And that’s obviously going to be a function of, in the case of Ion, how we adopt in lung cancer biopsy over time. And with SP, it’s the additional indications and new geographies in terms of clearances. I don’t have a scale for when we might reach those corporate average margins. I would say though for 2022, given that SP and Ion are newer products, the gross margins there are dilutive as you would expect.
Rick Wise — Stifel — Analyst
Yeah. And just a follow-up from me. I mean, it’s clear you highlighted multiple times multiple ways that Asia performed well this quarter. If I understood you correctly, procedures, I think you said were robust. And I’m just thinking about that thought in conjunction with your comments about where you’re investing. And it sounds like a lot of the investments were in Asia. And I was just wondering if we should just — how do I ask this? Does this suggest that you’re thinking as we look over the next three to five years that there is more growth for — or more growth opportunity for Intuitive in the Asia-Pacific region, or how do we — how do I think about those two facts and those initiatives if that makes any sense? Thank you.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
I’d characterize it a little bit differently, Rick. The starting point on Asia, it is clearly an interesting market country by country. We are making investments in Asia. I don’t think I’d say that they are the dominant investments, but they’re substantial because we think there is substantial opportunity there to make a difference in those markets. So, it’s a leg of growth but not the only one. There are opportunities for us in other regions, whether it’s Europe or elsewhere. There are also opportunities for us in other clinical indications and some of the clinical trial work we’re doing as well as the expansion of platforms and other technologies that we’re working on. So, I’d characterize it as one of the legs, not necessarily the dominant leg.
Jamie, anything you would like to add?
Jamie Samath — Chief Financial Officer
I would just say, both regions are attractive to us. It’s fair to say, at least in the last couple of years, Asia procedure growth has been a little ahead of Europe. But on a strategic view, both of those regions are attractive and we’re investing accordingly.
Rick Wise — Stifel — Analyst
Thanks so much.
Operator
Our next question will come from the line of Matt Taylor from UBS. Please go ahead.
Matt Taylor — UBS — Analyst
Hi, guys. Thanks for taking the question. So, I wanted to ask one on innovation and one on competition. So, on innovation, I appreciate some of the color that you gave on multiport and — as I’ve have also noticed, you’ve, on your website, been hiring a lot of folks in kind of these endoluminal roles and looking at roles around things like node surgery. Could you talk about some of your investments there? Is there anything beyond what you’re doing with SP and Ion that we should look out for? And overall, are there any bigger launches that we should expect this year, even if you’re not going to tell them what they are? Could you characterize what the cadence could look like of any kind of system upgrades or launches?
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Yeah. On the — with regard to kind of forecasting future launches, of course, we won’t give you any detail here. We’ll launch them when we’re ready to launch. In terms of the framing of your question, we are routinely developing applications for the platforms we have, whether it’s bariatrics and thoracic surgery, in our multiport indications to new indications and SP. And we’re doing some trials on thoracic surgery and colorectal to new opportunities in flexible robotics and Ion. And other platform investments that are currently not disclosed, things that we’re working on.
So we’re going to continue to do that and some of them will come to fruition and be fantastic and some of them may be things that we assess and then pivot as we learn more. So there is all of those things going on and somebody was out scanning what we’re hiring and scanning the kinds of patent applications we have, you will see a great diversity of things we’re interested in. It’s a little bit like the first question on the call when we say what are we talking about in terms of possibility. We really scour the acute intervention opportunity from the bottom of your feet to the top of your head and everything in between and start asking questions about whether we think there’s a real opportunity for improvements in the quad aim and whether we could design a tech-enabled ecosystem to do something about it. That’s what informs a lot of that hiring. Some of it is near-term and in existing platforms and some of it’s future oriented on platforms that may come to pass. So that’s kind of how we think about it.
Matt Taylor — UBS — Analyst
Okay. Thanks for that. And maybe just one on competition.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
Matt, we’ll give you one follow-up.
Matt Taylor — UBS — Analyst
Okay. Just on competition, you mentioned there is a potential for that to prolong selling cycle. It certainly doesn’t seem like you’re seeing any of that so far. Could you characterize whether there’s any change in the competitive environment to date versus a few quarters ago?
Jamie Samath — Chief Financial Officer
Certainly you can see the competition is active accounts. I think we characterize that mostly as kind of reciprocal arrangements with respect to training center investments or reciprocal research investments. I don’t think we call out any specific significant impact yet on selling cycles, but certainly you can see the potential for it over time.
Matt Taylor — UBS — Analyst
Okay. Great. Thanks, Jamie.
Gary S. Guthart — Chief Executive Officer, Member of the Board of Directors
All right. Well, thank you all. That was our last question. In closing, we continue to believe there is a substantial and durable opportunity to fundamentally improve surgery and acute interventions. Our teams continue to work closely with hospitals, physicians and care teams in pursuit of what our customers have termed the quadruple aim. Better, more predictable patient outcomes, better experiences for patients, better experiences for their care teams, and ultimately, a lower total cost of care. We believe value creation in surgery and acute care is foundationally human. It flows from respect for and understanding of patients and care teams, their needs and their environment. At Intuitive, we envision a future of care that is less invasive and profoundly better, where diseases are identified earlier and treated quickly so patients can get back to what matters most.
Thank you for your support on this extraordinary journey. We look forward to talking with you again in three months.
Operator
[Operator Closing Remarks]