Technical evolution and short-term outcomes of minimally invasive versus conventional open anterior cervical discectomy and fusion: a systematic review and meta-analysis.

backgroundConventional open anterior cervical discectomy and fusion (ACDF) is an established treatment for degenerative cervical disease, but approach-related morbidity remains a concern. Minimally invasive anterior cervical techniques have evolved from microscope-assisted mini-open procedures to endoscope-assisted and selected full-endoscopic approaches. This study systematically reviewed the technical evolution of minimally invasive ACDF-related procedures and compared perioperative and short-term outcomes with conventional open ACDF.

methodsThis systematic review and meta-analysis was conducted in accordance with PRISMA. PubMed, Embase, Web of Science, and the Cochrane Library were searched. Comparative studies were included in the quantitative synthesis, whereas selected non-comparative anterior endoscopic reports were retained for qualitative contextualization of technical evolution. Risk of bias in comparative nonrandomized studies was assessed with ROBINS-I. Random-effects meta-analysis was used to pool mean differences (MDs) and odds ratios (ORs). Because pain outcomes were reported using non-uniform anatomical constructs, VAS data were summarized qualitatively rather than pooled. Studies that reported only category-specific adverse events without clear patient-level totals were excluded from the pooled analysis of overall complications to avoid double-counting.

resultsEight studies were included. Five comparative studies involving 347 patients were quantitatively synthesized, and three additional reports informed the qualitative analysis. Minimally invasive ACDF was associated with lower intraoperative blood loss than open ACDF (MD -21.93 mL, 95% CI -31.30 to -12.56; P < 0.00001; I² = 74%)). No significant between-group differences were observed for postoperative dysphagia (OR 0.71, 95% CI 0.21 to 2.43; P = 0.58), overall complications (OR 0.39, 95% CI 0.14 to 1.04; P = 0.06), length of stay (MD -0.55 days, 95% CI -1.20 to 0.11; P = 0.10), JOA (MD 0.48, 95% CI -0.05 to 1.01; P = 0.08), or NDI (MD -0.39, 95% CI -1.33 to 0.56; P = 0.42). Pain outcomes improved in both groups across individual studies but were not meta-analyzed because reported pain definitions differed across studies.

conclusionsMinimally invasive ACDF may reduce intraoperative blood loss while providing short-term neurological, disability, and complication outcomes broadly comparable to conventional open ACDF. Better-standardized comparative studies, particularly with harmonized pain definitions and blood-loss reporting, are needed.

trial registrationPROSPERO CRD42026001353049, retrospectively registered on 27 March 2026.