title: Sacro-Iliac Joint Sensory Block and Radiofrequency Ablation: Assessment of Bony Landmarks Relevant for Image-Guided Procedures.
abstract: Image-guided sensory block and radiofrequency ablation of the nerves innervating the sacro-iliac joint require readily identifiable bony landmarks for accurate needle/electrode placement. Understanding the relative locations of the transverse sacral tubercles along the lateral sacral crest is important for ultrasound guidance, as they demarcate the position of the posterior sacral network (S1-S3 ± L5/S4) innervating the posterior sacro-iliac joint. No studies were found that investigated the spatial relationships of these bony landmarks. The purpose of this study was to visualize and quantify the interrelationships of the transverse sacral tubercles and posterior sacral foramina to inform image-guided block and radiofrequency ablation of the sacro-iliac joint. The posterior and lateral surfaces of 30 dry sacra (15 M/15 F) were digitized and modeled in 3D and the distances between bony landmarks quantified. The relationships of bony landmarks (S1-S4) were not uniform. The mean intertubercular and interforaminal distances decreased from S1 to S4, whereas the distance from the lateral margin of the posterior sacral foramina to the transverse sacral tubercles increased from S1 to S3. The mean intertubercular distance from S1 to S3 was significantly (p< 0.05) larger in males. The interrelationships of the sacral bony landmarks should be taken into consideration when estimating the site and length of an image-guided strip lesion targeting the posterior sacral network.
authors.affiliation: Division of Anatomy, Department of Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Trevor J G
authors.identifier: 0000-0003-3860-0135
authors.initials: TJ
authors.lastname: Robinson
authors.affiliation: Division of Anatomy, Department of Surgery, University of Toronto, Toronto, ON, Canada.
authors.forename: Shannon L
authors.initials: SL
authors.lastname: Roberts
authors.affiliation: Division of Physical Medicine and Rehabilitation, University of Alberta, Edmonton, AB, Canada.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Burnham
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Western Ontario, London, ON, Canada.
authors.forename: Eldon
authors.initials: E
authors.lastname: Loh
authors.affiliation: Division of Anatomy, Department of Surgery, University of Toronto, Toronto, ON, Canada; Division of Physical Medicine and Rehabilitation, Department of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Agur
mesh_terms: D059925:Anatomic Landmarks / Q000000981:diagnostic imaging* / Q000601:surgery; D002102:Cadaver; D017115:Catheter Ablation / Q000379:methods*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D009407:Nerve Block / Q000379:methods*; D015203:Reproducibility of Results; D012446:Sacroiliac Joint / Q000294:innervation / Q000601:surgery*; D012447:Sacrum / Q000000981:diagnostic imaging* / Q000601:surgery; D012680:Sensitivity and Specificity; D013127:Spinal Nerves / Q000000981:diagnostic imaging / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome