{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T19:33:21Z","timestamp":1790192001443,"version":"4.1.0"},"reference-count":22,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T00:00:00Z","timestamp":1786579200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      Spinal manipulation is widely used in clinical practice, yet how contact site selection influences mechanical transmission through spinal structures remains poorly understood. This exploratory study characterizes the biomechanical transmission of impulsive spinal manipulative thrust (SMT) forces through the\n                      <jats:italic>in vivo<\/jats:italic>\n                      human lumbar spine, examining how contact site and vertebral level alter the mechanical and neuromuscular response.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Four patients undergoing elective lumbar surgery were instrumented with triaxial accelerometers on intraosseous Steinmann pins at L2 and L4, and bilateral needle electromyographic (nEMG) electrodes. An Impulse iQ adjusting instrument delivered impulsive SMTs to six contact points in randomized order: L3 spinous process, L5 spinous process, and bilateral L2 and L4 facet joints totaling 1,549 usable for force-dependent analyses after excluding one patient with an instrument force malfunction. Patient-level aggregation (n = 3\u20134) served as the primary statistical approach.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Two patterns of mechanical transmission were observed. Spinous process contacts produced larger posterior-anterior vertebral acceleration at L2 in all patients (14.95 \u00b1 10.97 vs. 6.75 \u00b1 4.62 g, patient-level\n                      <jats:italic>P<\/jats:italic>\n                      = 0.066), while facet contacts produced larger cranial-caudal acceleration at L4 (2.50 \u00b1 2.27 vs. 0.94 \u00b1 0.59\u00a0g). L3 spinous contacts produced substantially greater L2 posteroanterior acceleration than L5 contacts (21.3 \u00b1 10.9 vs. 8.2 \u00b1 5.8 g, patient-level\n                      <jats:italic>P<\/jats:italic>\n                      = 0.021), with proximity-dependent inter-vertebral attenuation reflected by transfer ratios of 0.094 (L3) versus 0.619 (L5). Facet contacts showed no significant bilateral asymmetry at the patient level.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>These exploratory findings suggest that contact site selection influences the transmission pathway architecture and directional character of the vertebral mechanical response during impulsive SMTs. These biomechanical observations may help generate hypotheses for future clinical studies examining the relationship between contact site selection and therapeutic outcomes.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fbioe.2026.1849593","type":"journal-article","created":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T08:13:51Z","timestamp":1786608831000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Mechanical transmission of impulsive instrument-assisted spinal manipulation: contact-site-dependent biomechanical coupling in the in vivo human lumbar spine"],"prefix":"10.3389","volume":"14","author":[{"given":"Christopher J.","family":"Colloca","sequence":"first","affiliation":[{"name":"Department of Kinesiology, College of Health Solutions, Arizona State University","place":["Phoenix, AZ, United States"]},{"name":"International Spine Research Foundation","place":["Dexterville, NY, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert","family":"Gunzburg","sequence":"additional","affiliation":[{"name":"Cavell Spine Centre, Edith Cavell Hospital","place":["Brussels, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mostafa Afifi","family":"Hegazy","sequence":"additional","affiliation":[{"name":"Department of Kinesiology, Southwest Minnesota State University","place":["Marshall, MN, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marek","family":"Szpalski","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics, Hospital Moliere Longchamp","place":["Brussels, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,13]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"447","DOI":"10.1067\/mmt.2000.108822","article-title":"Neurophysiologic response to intraoperative Lumbosacral spinal manipulation","volume":"23","author":"Colloca","year":"2000","journal-title":"J. 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