Is there Still an Argument for Fusion of Lumbar DDD? - Michael Janssen, DO

1. Select on the "4 Ps" — and operate only when they align. Janssen judges every candidate on Pain, Pathology, Protoplasm (tissue/bone quality), and Personality (realistic goals, psychosocial stability). When these don't match — e.g., the anatomy is treatable but the patient has lost their job, is on narcotics, and has two attorneys — no technically correct operation will produce a good functional result. The red flags are clinical, not just radiographic, and you should weigh them before you ever look at the implant. 2. Change what you measure: fusion measures fusion, arthroplasty measures function. For decades the primary endpoint of a fusion was whether it fused, and that endpoint told us surprisingly little about how the patient actually did. Arthroplasty forced the field to track function — VAS, ODI, return to work and activity — over long horizons. When you counsel a patient, define success as functional recovery, not the appearance of the postoperative film. 3. The ideal arthroplasty candidate has a "painful, anterior-accessible disc." Symptomatic, function-limiting, single- or two-level disease over a disc you can safely reach from the front. Morbid obesity, prior abdominal or vascular surgery, lymph node dissection, or difficult vascular anatomy can make a disc not anterior-accessible — and that, not the disc pathology itself, may be the deciding factor. Janssen advocates preoperative CT angiography to map the bifurcation and confluence, minimize the incision, and avoid intraoperative surprises. 4. Arthroplasty maintains motion; it does not create it — so the release is the operation. A disc, like a knee, only preserves movement that's still there; if you curette out the disc and drop an implant in the way you'd do a fusion, you've implanted "an expensive fusion device." Getting real motion requires meticulous anterior and posterior release. Matched with the right patient, that translates to a genuinely faster recovery — Janssen cites protecting patients for only about six weeks, with power-boat racers back to high-G activity in weeks. 5. Fusion is still the right answer for the right phase of disease. Use the dental analogy: different phases warrant different treatments. Gross instability, deformity, spondylolisthesis, and badly incongruous or sagittally oriented facets are fusion indications — arthroplasty treats a phase, not everything. Janssen's own caution ("friends don't fuse friends") is specifically about one- and two-level degenerative disease without instability, deformity, or severe facet disease, where he argues fusion becomes an "annuity surgery" driving reoperation and adjacent-level disease. 6. Take bone quality seriously, and know the limits of the numbers. Janssen now obtains a T-score on 100% of arthroplasty candidates after being burned by subsidence and a pinser fracture in patients who "should" have had normal bone. His practical threshold sits near -1.0, but the panel stresses the score is logarithmic, arbitrary at the margins, and imperfectly correlated with Hounsfield units (which measure cancellous bone versus DEXA's cortical rim). Osteopenia below threshold warrants a metabolic workup — and, in motivated patients, teriparatide can meaningfully improve bone before surgery. Note too that Modic changes are not an evidence-based inclusion or exclusion criterion despite some payers adopting them. 7. Distinguish true adjacent-segment disease from independent natural history — and learn openly from complications. As the case discussion showed, a degenerative spondylolisthesis at L4-5 above an L5-1 arthroplasty is often a standalone, facet-driven problem, not "proof the disc failed." Arthroplasty reduces, but does not abolish, adjacent-level degeneration — we all keep aging. Meanwhile, actual mechanical failure rates (removal/revision) run roughly 1-3%, often below total hip and knee revision rates, and most complications trace to a fixable error: wrong indication, poor planning, wrong size or position, inadequate release, or overreaching to two and three levels (the "bowling balls balanced on a 2×4"). Show your complications, because that's where the real teaching is.