Ethics Corner | July 2022
by Craig Louer, MD
An adolescent patient elects to proceed with posterior spinal fusion (PSF) for AIS. The curve is classified pre-operatively as Lenke 1C-, characterized by a structural main thoracic curve with significant hypokyphosis; and, the clinical exam correlates with this sagittal plane disruption. The main thoracic (MT) coronal Cobb measures 55 degrees and it demonstrates reasonable flexibility in the coronal plane. This surgeon would not typically use posterior column (Ponte-style) osteotomies to improve correction for a main thoracic curve like this in isolation. However, in this particular case, a selective thoracic fusion is the chosen surgical approach and the surgeon hopes to maximize MT correction to better influence spontaneous lumbar curve correction.1 The surgeon uses this as justification to perform 5 apical Ponte osteotomies during the procedure. Surgery is complicated by intra-operative neuromonitoring alerts but ultimately no neurologic deficit is noted at wake-up test or final outcome. Desired correction is achieved, and patient has a routine post-operative course subsequently.
Afterwards, the surgeon considers the ethical underpinnings of the decisions made, including:
"How much increased surgical risk is tolerable for incremental gains in correction with uncertain influence on ultimate long-term outcomes?"
Or to phrase another way,
"If this patient suffered significant or irreversible neurologic deficit as a result of Ponte osteotomies, would the potential or realized gains of such a strategy be adequate justification?"
Although rarely do surgeons ask themselves these questions explicitly, they are nonetheless encountered and addressed by our routine decisions. Each of us has been honed during training and practice to be passable judges of relative risk and benefit. Every surgical indication considers relative risk and benefit of a procedure and whether this balance is "acceptable".
The topic of acceptable risk for Ponte osteotomies in AIS has been an area of internal debate for me as a young surgeon, as well as a public and sometimes fervent debate within our specialty. Ponte osteotomies are routinely performed for all curves in some practices, while in others it is a rarity only for extenuating circumstances.2 Controversial and sometimes opposing viewpoints have been presented during research podiums at national meetings, making the dichotomy in practice patterns relatively apparent. Why would a group of surgeons who seem to agree on the favorable benefits-to-risks ratio for a procedure like PSF for AIS have opposing viewpoints on the related procedure of Ponte osteotomies? Perhaps it is because we do not agree to the same set of facts like we do for PSF.
The Ponte osteotomy was developed in 1987 by Dr. Alberto Ponte of Rome, Italy. It was originally developed for kyphosis, but it has been noted more recently by its creator to have ability to correct coronal and rotational deformities in addition to sagittal deformity.3 Within the last decade there have been numerous reports of incorporating Ponte osteotomies into the PSF procedure for AIS, with general improvements in coronal, sagittal, and axial corrections compared to controls, though the studies are observational and the clinical significance of the modest improvements are debatable.4,5 One situation where these small changes in deformity characteristics may be clinically relevant is in the situation of a selective thoracic fusion where spontaneous lumbar curve correction appears to be influenced by the magnitude of coronal correction and, to a lesser degree, the kyphosis restoration.1
In other cases, it is speculated that restoration of thoracic kyphosis is the most essential component of deformity correction, as this kyphosis restoration may positively influence overall sagittal profile by allowing physiologic lumbar lordosis and reducing the presence of cervical kyphosis.6,7 Long-term follow-up may help determine whether these purported benefits will affect healthcare related quality of life, though there is sparse evidence of an immediate or mid-term advantage in outcomes attributable to Ponte osteotomies for AIS.
The performance of Ponte osteotomies has been associated with additional risks. In a large series of 2210 patients, Buckland et.al. reports a risk of realized neurologic complication to be quite low and similar between AIS groups undergoing PSF with Ponte Osteotomy (PO) or No PO (0.37% vs. 0.17%). Although no statistical difference in the manifested complications, there was a significantly increased rate of neuromonitoring alerts in the group undergoing POs (9.3% vs. 4.2%).8 Additional studies have substantiated that the risk of a neuromonitoring alert is increased if Ponte osteotomies are utilized.9 There are other potential risks with Ponte osteotomy use, including increased blood loss, operative time, and concern for wound issues if hematoma were to form.
Proponents of Ponte osteotomies would argue that PSF is a deformity correction operation, and the Ponte osteotomy is a powerful tool to help them best achieve maximum correction. These individuals recognize that it will cost them some time and may result in increased neuromonitoring alerts. However, they do not weigh the risk of neurologic injury to be significantly increased over baseline. Detractors of this practice would state that neuromonitoring alerts are a critical outcome meant to be avoided. These surgeons believe that they can accomplish their PSF goals of limiting future progression with a minimal risk operation and they perhaps don’t believe maximum radiographic correction in all three planes is a goal that warrants additional risk.
The other significant consideration that must be acknowledged is the impact of reimbursement in our decision-making. Many surgeons have compensation plans that are productivity-based, where at least part of their salary is determined by clinical productivity measured by work-RVUs (wRVU). The code for a single posterior column osteotomy (PCO) (thoracic-level CPT 22212) is worth 20.99 wRVU; a lumbar PCO is worth slightly more. In the current system, this means a single PCO would generate more wRVU than open treatment of femoral shaft fracture (CPT 27506, wRVU-19.65) and over 70% of the wRVU of a suboccipital and cervical decompression for Arnold-Chiari malformation (CPT 61343, wRVU 31.86). While additional levels of PCO don’t generate wRVUs quite as generously as the initial PCO (CPT 22216, wRVU 6.03), PCOs collectively have a large effect on the procedural charge and reimbursement.
While we assume (and hope) that there are very few surgeons who make decisions solely based on billing, the realities of reimbursement may subconsciously sway many more surgeons who understand the impact it has on their (or their hospital’s) bottom line. Cognitive dissonance can lead to rationalization to use PCOs for a medical indication, though the subconscious motivation is repayment. Any productivity-based surgeon who knows how they are reimbursed is subject to such bias. Pretending it does not exist would be naïve.
As for the solution to this ethical dilemma, unfortunately there is no clear answer. The well-known clinical ethical principles of beneficence and non-maleficence are at odds with many cases of surgical decision-making. With these two principles in conflict, determination of which should prevail would depend on weighing an individual surgeon’s interpretation of the data. The answer may vary for each surgeon or patient, with risks somewhat mitigated with more surgical experience or skill, or the benefits more pronounced in some patients where routine measures will not result in an acceptable outcome. As evidence evolves, new patients seek care, and we continue to change as individual surgeons, I submit that this decision should change in accordance. Do not be blind to your biases and subconscious motivations. Continued introspection and re-evaluation is essential in surgery. Ask yourself: “If a complication were to result from the performance of this Ponte osteotomy, would I still feel performing the procedure was necessary and was the best decision for this patient?” Also ask, “Would I make the same decision if payment were unaffected?” When these are answered in the affirmative, then your assessment favors the performance of a Ponte osteotomy.
1. Kluck D, Sullivan TB, Bastrom TP, Bartley CE, Yaszay B, Newton PO. Predictors of spontaneous lumbar curve correction in thoracic-only fusions: 3D analysis in AIS. Spine Deform. 2021;9(2):461-469. doi:10.1007/s43390-020-00231-0
2. Oetgen ME, Weinstein SL, Andras L, Shah S, Sucato DJ. What are Your Optimal Surgical Strategies for a Double Major Curve in Adolescent Idiopathic Scoliosis? 2020;2(1):28.
3. Ponte A, Orlando G, Siccardi GL. The True Ponte Osteotomy: By the One Who Developed It. Spine Deform. 2018;6(1):2-11. doi:10.1016/j.jspd.2017.06.006
4. Samdani AF, Bennett JT, Singla AR, et al. Do Ponte Osteotomies Enhance Correction in Adolescent Idiopathic Scoliosis? An Analysis of 191 Lenke 1A and 1B Curves. Spine Deform. 2015;3(5):483-488. doi:10.1016/j.jspd.2015.03.002
5. Shah SA, Dhawale AA, Oda JE, et al. Ponte Osteotomies With Pedicle Screw Instrumentation in the Treatment of Adolescent Idiopathic Scoliosis. Spine Deform. 2013;1(3):196-204. doi:10.1016/j.jspd.2013.03.002
6. Newton PO, Yaszay B, Upasani VV, et al. Preservation of Thoracic Kyphosis Is Critical to Maintain Lumbar Lordosis in the Surgical Treatment of Adolescent Idiopathic Scoliosis: Spine. 2010;35(14):1365-1370. doi:10.1097/BRS.0b013e3181dccd63
7. Feng J, Zhou J, Huang M, Xia P, Liu W. Clinical and radiological outcomes of the multilevel Ponte osteotomy with posterior selective segmental pedicle screw constructs to treat adolescent thoracic idiopathic scoliosis. J Orthop Surg. 2018;13(1):305. doi:10.1186/s13018-018-1001-0
8. Buckland AJ, Moon JY, Betz RR, et al. Ponte Osteotomies Increase the Risk of Neuromonitoring Alerts in Adolescent Idiopathic Scoliosis Correction Surgery. Spine. 2019;44(3):E175-E180. doi:10.1097/BRS.0000000000002784
9. Floccari LV, Poppino K, Greenhill DA, Sucato DJ. Ponte osteotomies in a matched series of large AIS curves increase surgical risk without improving outcomes. Spine Deform. 2021;9(5):1411-1418. doi:10.1007/s43390-021-00339-x