Durability of Endoscopes Used During Routine Lumbar Endoscopy: An Analysis of Use Patterns, Common Failure Modes, Impact on Patient Care, and Contingency Plans

DISCUSSION

This retrospective study on a total of 120,150 lumbar endoscopies done by 85 surgeons in various private or academic, single- or multispecialty practice settings in 16 countries determined the estimated average life cycle of a spinal endoscope used in routine lumbar decompression surgeries for herniated disc or stenosis of the spinal canal is between 50 and 100 cases–less than half the number most manufacturers suggest in their instructions for use that the end user should reasonably expect if their product is used and processed according to their recommended guidelines for use, cleaning, and sterile processing. How can this stark difference be explained? The answer may perhaps be rather obvious. The regulatory process mandated by the respective agencies governing the mandatory self-certification marks required on many types of products to enter the Common (EU) European market (CE Mark), the United States market requiring approval by the Food and Drug Administration (FDA), or the China CCC Certification, China Customs, or India BIS Certification just to name a few, dictate the testing conditions. The life cycle numbers listed in endoscope manufacturers instructions for use are based on a benchtop in vitro testing scenarios which do not account for the human factor. Both surgeon use and improper handling by staff may contribute to lower actual life cycle usage numbers. Why is this important? It is simple. The added cost per case of introducing the endoscopic equipment has to be taken into account when implementation of an endoscopic spine surgery program is being considered at a hospital or an ASC. This notion was of particular importance to spine surgeons from China, where spinal endoscopy rather than an operating microscope was introduced in many hospitals because of the latter’s higher capital purchase cost. The authors’ observations put things in a very different light, though, considering that the average spinal endoscope lasts only 100 cycles. At an average capital purchase price of $10 000 for a spinal endoscope in China, the added case cost for purchasing and maintaining a spinal endoscopy program would be $100.

While clinical benefits have been demonstrated with the lumbar endoscopic decompression procedure in numerous peer-reviewed articles,11,20–41 high implementation and maintenance cost remains of concern to most healthcare institutions as the downstream cost savings may not be realizable within the same organization. Spinal endoscopy is, in fact, competing to replace traditional open and other forms of MIS, which are being performed without the need for additional large upfront capital- and disposable equipment purchases. The pressure for cost savings in already overstretched healthcare systems is high in most countries, and new technology implementation is often weighted against its cost vs benefit. Many hurdles entirely unrelated to patients’ clinical benefits may exist and impede the transition to these more modern innovative endoscopic spinal surgery protocols. Similarly, the pressure on endoscopic equipment manufacturers and associated vendors, who struggle with the higher burden of new regulatory rules, is insurmountably high, thus getting in the way of implementing innovative business models with sustainable revenue cycles.

Recently, the CE Mark regulation has changed from the Europe Standard EN 60950–1 to EN 62368–1 under which all audio/video (A/V) and information, communication technology (ICT) equipment sold in Europe will have to comply with the new EN 62368–1 hazard-based standard by December of 2020. This also applies to all existing equipment currently CE marked under EN 60950–1. In 2017, the European Parliament passed legislation to transition the EU’s medical device directive (MDD) to the more rigorous medical device regulation (MDR). This move was prompted by the MDD’s notifying body’s lack of oversight of a French breast implant manufacturer who had substituted high-quality medical silicone gel with low-quality industrial silicone in its breast implants, causing several casualties. Lawsuits for different varieties of negligence were also settled. The MDD was revised and reissued as the MDR and significantly expanded the accountability for future legal damages to virtually all economic operators (eg, authorized representatives, importers, distributors, etc). These increased reporting requirements and accountability criteria have increased the scrutiny on risk assessment documentation, technical files, and quality-control processes raising production costs disproportionally higher for manufacturers of spinal endoscopes, who face the same cost of MDR implementation but operate in a small niche market plagued by inconsistent demand. This higher regulatory burden will likely stifle rapid technological innovation needed to advance clinical protocols as the cost for change is too high. The higher regulatory burden in Europe and North America could skew the playing field in other markets where lower-cost products may have an advantage. Complaints from manufacturers as of this article’s writing have halted complete MDR implementation in Europe, and the stakeholders continue to debate the way forward. Ultimately, this ongoing dynamic may play out in operating rooms worldwide considering most spinal endoscope manufacturers, including OEM makers, reside in Europe.

As with any new technology, formalized postgraduate training lags. This postgraduate training gap was also reflected in the responses given by participating surgeons regarding the endoscopic specialty training. While 29.4% completed a formal 6 to 12 months MIS spine fellowship, 45.9% of surgeons indicated that they received their spinal endoscopy training in a short weekend workshop. Another 29.4% had been able to find a mentor as a training resource. Nevertheless, a significant portion of responding spine surgeons (16.5%) were self-taught, which highlights the fact that many of the younger surgeons–44.7% of respondents were between the ages 35 and 44 years–have to figure out by themselves how to implement a spinal endoscopy surgery program and develop contingency plans for intraoperative failure of the spinal endoscopy system.

One of the most convincing findings of this study relates to the rising surgical case volume done with endoscopic minimally invasive techniques. Some 12,650 of the 120,150 captured by this team of authors were done within the past year. While the authors had no way of determining a trend, it was apparent that the case volume by younger surgeons coming online is substantially increasing, considering 10.5% of the entire case volume was done just within the past year (as of the date of terminating the survey). Transforaminal endoscopic decompression surgery was the favorite among spine surgeons, with 76.5% indicating that they employ it routinely. The interlaminar approach was employed by surgeons at a lower rate, with surgeons reporting that they used it in 51.8% of their cases. UBE was of low relevance in this study. Over half (55.3%) of the surgeons participating in this survey were less experienced with 5 or fewer years of clinical experience with the spinal endoscopy procedure. Although we could not establish a statistically proven correlation with the type of surgical approach, surgeon skill level, annual case numbers, use of motorized power instruments, bad handling by staff, and vendor, all of these factors likely play into the cumulative damage of spinal endoscopes that eventually fail. While the burden to improve resistance to frequent sterilization cycles is clearly on the manufacturing side, some surgeon-related failure modes stand out; for example, the endoscope tip is a regular site of damage to the lens, the fiberglass light carrier, the seal between all components. Retracting power burrs while still running against the lens will invariably destroy it. The uncontrolled use of side-firing lasers may have a similar effect. Some manufacturers have attempted to make the lens components more robust by gold welding it in place, but as shown in one case example (Figure 7), it may still fail. Nearly a quarter (23.5%) of responding spine surgeons had a spinal endoscope that failed during surgery. Some 66.3% had a replacement endoscope available and another 36.1% of surgeons were able to complete the surgery with the broken endoscope. However, 10.8% stopped and another 6% of surgeons woke the patient up and rescheduled the surgery to complete the decompression at another time, thus, highlighting the need for contingency plans for such endoscopic equipment failures illustrated in Figures 8 and 9.

Ultimately, this article is a plea to endoscopic spine surgeons and the makers of this hightech equipment alike to work collaboratively on practical solutions to the everyday problems reported herein. Hopefully, that will entail continued technology improvements. However, it also calls for improved training of surgeons and their staff on handling and processing, establishing well-controlled custody chains of the instrumentation while controlling implementation cost, and not inflating the case cost for lumbar decompression procedures. The reimbursement structure in the United States is currently in a reverse relationship to implementation cost. Spinal endoscopy costs more and reimburses less. Since 2016, there has been a current procedural terminology (CPT) code addition (62380) that provides a billing code for endoscopic decompression of the spinal cord or nerve roots at the lumbar level. However, the relative value units (RVU) proposed by the Centers for Medicare Services (CMS) in 2016 based on the intensity and an identical intraservice time was 9.09 with a final conversion factor in 2017 of $35.89 per RVU. The American Medical Association/Specialty Society Relative Value Scale Update Committee (RUC) recommended a work RVU of less than the 10.47 number based on a crosswalk to CPT code 47562 (Laparoscopy, surgical; cholecystectomy) since CMS at the time stipulated that CPT codes 62380 and 47562 are similar in intensity but that the work involved in furnishing CPT code 62380 was overestimated. The malpractice, facility expenses, and total facility RVU numbers were undiscoverable for 62,380 at the time of this article’s writing. In comparison, CMS recommended in 2018 a work RVU of 13.18, facility expense RVU of 10.95, malpractice RVU of 4.06, and total facility RVU of 28.19 for CPT code 63030 (laminotomy). For laminectomy (CPT code 63046), the respective 2018 RVU numbers were work RVU of 17.25, facility expense RVU of 12.90, malpractice RVU of 5.43, and total facility RVU of 35.58.42 This glance at the US reimbursement landscape highlights the importance of good stewardship with any endoscopic spine surgery program if it is to be rolled out across the board and not just to a few patients who can afford it.

Our retrospective survey study was plagued by the same bias limitations as any other retrospective and survey study. Our response rate of 27.1% is on par with previously reported online surveys. The average response rates for an in-person survey have been reported at 57%, mail survey at 50%, email survey at 30%, online survey at 29%, telephone survey at 18%, and in-app survey of 13%, rendering the overall average survey response rate of 33%.43–47 Responses were blinded, and the authors had no information about the identity of the responding spine surgeons limiting the impact of intuition and hindsight bias among the investigators.48 The effect of nonresponse bias due to the low response rate may improve survey accuracy and was of no concern to this team of authors since low response rates in the 20% range have been related to more accurate measurements than surveys with 60% to 70% response because the missing data are not random.49 Additional limitations may have arisen from geographic bias. The digital communication used in this survey study could have obliterated existing geographic diversity and various cultural perspectives of responding to spine surgeons. The authors assumed a negligible impact of geographic bias factors because statistical testing did not affect geographic or cultural factors in the collected data. Instead, the authors were cautious not to generalize this retrospective survey’s findings in the context of their preconceived notions of endoscopic instrumentation failure to counter the homogenizing effect of the digital data acquisition across multiple geographical and cultural boundaries. Hindsight and recall bias by the responding surgeons may have been the most relevant limitations of this study since the information presented herein was not based on a patient registry but was based on the surgeon’s ability to recall the specific details surrounding the intraoperative failure of the endoscope and resist the influence of clinical outcome knowledge, which are anchored in reconstructive memory (hindsight bias).48 The authors recognized that their personal experience with endoscope failure during routine lumbar endoscopy might have been different and acknowledged the genuinely alternative insights from other surgeons.