Neck fusion surgery for segmental neck pain helps only about half of patients, Swedish registry study finds

Neck fusion surgery performed for a controversial diagnosis known as segmental neck pain delivered clinically meaningful improvement in only about half of the patients who received it, according to a nationwide Swedish registry study published in Acta Neurochirurgica. The study, led by researchers including Ahmed Haydar Sameer and Victor E. Staartjes, drew on nearly two decades of data from the Swespine national spine registry and found that most of the benefit that did occur emerged within the first year after surgery, with little additional improvement thereafter. The authors conclude that their findings do not support recommending surgery for this indication.

Anterior cervical discectomy and fusion, or ACDF, is one of the most commonly performed procedures in spinal surgery worldwide. For those indications, previous studies have shown effective and rapid improvements in pain, neurological symptoms, and functionality. But the operation is also sometimes performed on patients whose only symptom is mechanically driven neck pain, a far more contested use, because the true source of the pain often cannot be reliably identified.

The Swedish study focused on a narrow subgroup of these patients. In Swedish clinical practice, the label segmental pain, or Segmentell rörelsesmärta, describes mechanically induced pain presumed to derive from a dysfunctional cervical segment. The diagnosis requires a history of mechanically provoked pain, imaging evidence of degenerative changes, and clinical findings of level-specific pain triggered by deep palpation that corresponds to the radiologic level of degeneration. Yet imaging findings are common and do not automatically identify the pain generator, and there are no standardised objective diagnostic criteria that reliably distinguish segmental neck pain from broader categories such as mechanical, non-specific, or axial neck pain. The identification of these patients therefore relies heavily on the surgeon’s clinical assessment of the primary pain generator.

To capture the national experience, the researchers searched Swespine, a national quality registry covering approximately 95 percent of spine surgery units in Sweden, for all patients who underwent ACDF with this registry-defined diagnosis between January 2006 and December 2024. Of 22,375 cervical procedures identified, only 130 carried the segmental neck pain diagnosis. After excluding 75 non-ACDF procedures, mainly posterior fixations without decompression, and removing patients without a baseline or postoperative neck pain rating, the final cohort comprised just 36 patients treated at 12 centers. The small size of the group itself underscores how rarely surgeons in Sweden have chosen to operate for this indication alone.

The typical patient was 51 years old, and half were male. Before surgery, patients reported substantial symptom burden: mean neck pain intensity of 7 on a 0-to-10 numeric rating scale, a mean Neck Disability Index score of 56, and a mean EQ-5D health-related quality-of-life index of 0.25. Ninety-four percent reported regular use of analgesic medication, and 23 percent had undergone previous cervical surgery. Most operations involved one or two levels, the mean hospital stay was three days, procedural complications were reported in one patient, and three patients required reoperation after the index procedure.

The researchers evaluated outcomes using patient-reported outcome measures at one, two, five, and ten years after surgery, applying established thresholds for the minimally clinically important difference, or MCID: at least a 40 percent relative reduction in neck pain intensity, at least a 33 percent relative reduction in disability, and at least a 0.08 absolute increase in the EQ-5D index. At one year, 55 percent of patients, 18 of 33, achieved the MCID for neck pain; 48 percent, 15 of 31, achieved it for disability; and 53 percent, 16 of 30, achieved it for quality of life. Patient satisfaction was somewhat higher, with 64 percent, 21 of 33, reporting satisfaction at one year, and satisfaction remained between 64 and 71 percent at all follow-up time points.

Perhaps the most striking pattern was the plateau. Most of the observed improvement in pain, disability, and quality of life was already present at the one-year mark, with no clear additional improvement at later follow-ups. Individual patient trajectories were markedly heterogeneous: some patients showed remarkable improvements across all measures, while others demonstrated minimal and fluctuating scores over time, and in some cases even worsening of reported symptoms. The researchers also noted a notable discrepancy between satisfaction and the pain and disability trajectories, with satisfaction remaining high even when the other measures did not improve proportionally. They suggest satisfaction may reflect patient expectations, a perceived solution to long-lasting symptoms, or acceptance of residual pain.

The authors are careful to stress what the study cannot show. Because there was no non-operative comparator group, no causality can be inferred, and improvements cannot be attributed to surgery rather than to the natural course of the condition, regression to the mean, or a placebo effect. The cohort was defined by a surgeon-reported registry diagnosis rather than independently verifiable criteria, and detailed diagnostic elements such as MRI findings, facet arthropathy, dynamic radiographs, provocative discography, and instability parameters were not available as structured registry variables, raising the possibility of misclassification. The registry also did not record the type, duration, or failure of preoperative conservative treatment, and the study was underpowered for any hypothesis testing, with all analyses purely descriptive. Response rates declined over time, with only 18 respondents at ten years, limiting interpretation of long-term outcomes.

The findings arrive in a field where comparative evidence is scarce. A systematic review cited in the paper identified no available comparative evidence against non-operative care for axial neck pain, and the closest comparison, covering three studies with a total of 166 patients, reported mean pain improvements of approximately 50 percent and satisfaction between 56 and 79 percent. In patients undergoing ACDF for other indications such as radiculopathy or myelopathy, 7 to 20 percent experience complete resolution and 54 to 64 percent partial resolution of neck pain at one year, but those findings do not establish any effect of ACDF in patients treated specifically for motion-provoked pain. Despite the inconsistent evidence, the latest Swespine report shows that surgery for segmental pain in the lumbar spine still accounted for 6 percent of all spinal surgeries in Sweden in 2024, underscoring that some patients continue to be selected for such operations.

The researchers write that their data provide observational evidence that cervical surgery is associated with early, clinically significant improvements in patient-reported outcomes in a subset of patients, and that the results may help inform clinical decision-making when conservative treatment fails. But they are equally explicit that the registry-derived findings do not support recommending surgery for segmental neck pain, given the lack of controlled studies, the small cohort, and the absence of objective standardised inclusion criteria. They call for future studies to prioritize objective selection criteria to refine patient selection and to clarify whether particular subgroups of patients with intractable chronic neck pain presumed to derive from segmental dysfunction might genuinely profit from surgery. Until such evidence exists, the Swedish experience suggests that fusion for neck pain alone remains an uncertain bet, with roughly half of carefully selected patients reporting meaningful benefit and the remainder experiencing little or no improvement.

Subject of Research: Outcomes of anterior cervical discectomy and fusion for presumed segmental dysfunction-related neck pain in a Swedish nationwide registry cohort

Article Title: Outcomes after anterior cervical discectomy and fusion for presumed segmental dysfunction-related neck pain: a Swedish nationwide registry study

Article References: Sameer, A. H., Nazar, Z., El-Hajj, V. G., Edström, E., Gerdhem, P., Elmi-Terander, A., & Staartjes, V. E. (2026). Outcomes after anterior cervical discectomy and fusion for presumed segmental dysfunction-related neck pain: a Swedish nationwide registry study. Acta Neurochirurgica, 168(1), Article 245. https://doi.org/10.1007/s00701-026-07076-y

Image Credits: AI Generated

DOI: 10.1007/s00701-026-07076-y

Keywords: ACDF, segmental neck pain, cervical fusion, Swespine registry, patient-reported outcomes, MCID, neck disability, EQ-5D, spine surgery, registry study, mechanical neck pain, surgical outcomes