Anatomical Comparison of Radiofrequency Ablation Techniques for Sacroiliac Joint Pain.

Objective: To compare the percentage of sacral lateral branches (LBs) that would be captured if lesions were created by seven current sacroiliac joint (SIJ) radiofrequency ablation (RFA) techniques: three monopolar and four bipolar. Design: Cadaveric fluoroscopy study. Setting: Anatomy and surgical skills laboratories. Subjects: Forty cadaveric SIJs. Methods: LBs were exposed, radiopaque wires were sutured to LBs, and anterior-posterior fluoroscopic images through the S1 superior endplate were obtained. Lesions that would be created by 17 versions of seven current SIJ RFA techniques were mapped on the fluoroscopic images. These 17 versions were compared: 1) percentage of LBs that would be captured; 2) percentage of SIJ specimens in which 100% of LBs would be captured; and 3) percentage of LBs that would not be captured at each level (S1-S4). Results: Both the mean LB and 100% capture rates were greater for the bipolar techniques (93.4-99.7% and 62.5-97.5%, respectively) than for the monopolar techniques (49.6-99.1% and 2.5-92.5%, respectively) evaluated. For the bipolar techniques, 1.5-29.2% of LBs would not be captured at S1 and 0% at S2-S4 vs 0-29.2% at S1-S4 for the cooled monopolar techniques vs 36.9-100% at S1-S4 for the conventional monopolar technique. Conclusions: The findings suggest that, if lesions were created, the RFA needle placement locations of the bipolar techniques evaluated may be capable of capturing all LBs, but those of the current monopolar techniques evaluated may not. Future in vivo imaging studies are required to compare the lesion morphology generated by different SIJ RFA techniques and correlate the findings with clinical outcomes.

A Controlled Trial Evaluating the Safety and Effectiveness of Ultrasound-Guided Looped Thread Carpal Tunnel Release.

Background: Open carpal tunnel release typically requires several weeks of recovery. A less invasive, ultrasound-guided percutaneous technique of releasing the transverse carpal ligament using a thread (thread carpal tunnel release [TCTR]) has been described. To date, its clinical effectiveness and safety have been evaluated exclusively by the group that developed the technique, using a single outcome measure without a control comparison. The objective of this study was to independently evaluate the safety and effectiveness of TCTR using multiple outcome measures and a control comparison. Methods: A convenience sample of 20 participants with refractory moderate or severe carpal tunnel syndrome underwent TCTR of their most symptomatic hand. Outcome measures included pre-TCTR and 1-, 3-, and 6-month post-TCTR Boston questionnaire; pre-, 3-, and 6-month post-TCTR monofilament sensibility, strength, ultrasound, and electrodiagnostic testing; weekly post-TCTR phone interviews for 1 month; and satisfaction surveys at 3 and 6 months post-TCTR. Results: No complications were reported. During the month post-TCTR, significant prompt improvements in hand pain and dysfunction occurred. The following significant improvements were demonstrated in the treated versus control hand: Boston Questionnaire scores, median nerve distal motor latency, transcarpal tunnel motor and sensory conduction velocities and sensory nerve action potential amplitudes. No significant differences in sensibility, pinch or grip strength, median nerve cross-sectional area (CSA) at the carpal tunnel inlet, or wrist: forearm median nerve CSA ratio were documented between TCTR and control sides. Satisfaction with the TCTR procedure was high (85%-90%). Conclusions: This study supports previous reports that the TCTR procedure is safe and effective.

A Cadaveric Study Evaluating the Feasibility of an Ultrasound-Guided Diagnostic Block and Radiofrequency Ablation Technique for Sacroiliac Joint Pain.

BACKGROUND AND OBJECTIVES: Ultrasound (US)-guided diagnostic block/radiofrequency ablation (RFA) along the lateral sacral crest (LSC) has been proposed for managing sacroiliac joint (SIJ) pain. We sought to investigate (1) ease of visualization of bony landmarks using US; (2) consistency of US-guided needle placement along the LSC; and (3) percentage of the posterior sacral network (PSN) innervating the SIJ complex that would be captured if an RFA strip lesion were created between the needles. METHODS: In 10 cadaveric specimens, 3 needles were placed bilaterally along the LSC from the first to third transverse sacral tubercles (TSTs) using US guidance. The PSN, SIJ, and needles were exposed, digitized, and modeled 3-dimensionally. Ease of visualization of bony landmarks, frequency of needle placement along the LSC, and percentage of the PSN that would be captured if an RFA strip lesion were created between the needles were determined. RESULTS: The LSC, TST2, TST3, and first to third posterior sacral foramina were easily visualized using US; TST1 was somewhat obscured by the iliac crest in some specimens. Needles were placed along the LSC in 18 of 20 specimens; in the first 2 of 20 specimens, needle 1 was placed at the L5/S1 facet joint. On average, 93% (95% confidence interval, 87%-98%) of the PSN would be captured if an RFA strip lesion were created between the needles. CONCLUSIONS: The findings suggest that US-guided needle placement along the LSC is consistent and could capture most or all of the PSN. A clinical study evaluating the outcomes of this technique is in progress.

Cadaveric study of sacroiliac joint innervation: implications for diagnostic blocks and radiofrequency ablation.

BACKGROUND AND OBJECTIVES: Optimization of clinical outcomes of lateral branch radiofrequency ablation or blocks for sacroiliac joint (SIJ) pain requires precise nerve localization; however, there is a lack of comprehensive morphological studies. The objectives of this cadaveric study were to document SIJ innervation relative to bony landmarks in 3 dimensions and to identify reference points visible under ultrasound and fluoroscopy for optimal needle placement. METHODS: In 25 cadaveric hemipelves, L5-S4 lateral branches were exposed, digitized, and modeled in 3 dimensions. The models were used to compare innervation patterns between specimens and to quantify the distances of the nerves innervating the SIJ relative to the transverse sacral tubercles (TSTs) and posterior sacral foramina. Quadrants of origin of the nerves were recorded. RESULTS: The SIJ was innervated by the posterior sacral network: S1-S2 contributed in all specimens, S3 in 88%, L5 in 8%, and S4 in 4%. Most frequently, the lateral branch(es) emerged from the inferolateral S1, superolateral and inferolateral S2, and superolateral S3 quadrants. All TSTs were easily identifiable elevations that were used to landmark the nerves innervating the SIJ. The majority of branches of the posterior sacral network crossed the lateral sacral crest between TST1-3, with the greatest concentration between TST2-3. Only 3 specimens had a branch superior or inferior to these landmarks. CONCLUSIONS: Based on the innervation pattern and using bony landmarks identifiable under ultrasound and fluoroscopy, 2 radiofrequency ablation techniques were proposed. Further research is required to determine the accuracy and reliability of needle placement and to evaluate clinical outcomes.

Determination of clinically relevant content for a musculoskeletal anatomy curriculum for physical medicine and rehabilitation residents.

To address the need for more clinical anatomy training in residency education, many postgraduate programs have implemented structured anatomy courses into their curriculum. Consensus often does not exist on specific content and level of detail of the content that should be included in such curricula. This article describes the use of the Delphi method to identify clinically relevant content to incorporate in a musculoskeletal anatomy curriculum for Physical Medicine and Rehabilitation (PM&R) residents. A two round modified Delphi involving PM&R experts was used to establish the curricular content. The anatomical structures and clinical conditions presented to the expert group were compiled using multiple sources: clinical musculoskeletal anatomy cases from the PM&R residency program at the University of Toronto; consultation with PM&R experts; and textbooks. In each round, experts rated the importance of each curricular item to PM&R residency education using a five-point Likert scale. Internal consistency (Cronbach's alpha) was used to determine consensus at the end of each round and agreement scores were used as an outcome measure to determine the content to include in the curriculum. The overall internal consistency in both rounds was 0.99. A total of 37 physiatrists from across Canada participated and the overall response rate over two rounds was 97%. The initial curricular list consisted of 361 items. After the second iteration, the list was reduced by 44%. By using a national consensus method we were able to objectively determine the relevant anatomical structures and clinical musculoskeletal conditions important in daily PM&R practice.

Intramuscular innervation of the human soleus muscle: a 3D model.

The purpose of this study was to document the neural distribution patterns within the human soleus muscle using 3D computer modelling. Through serial dissection, pinning, and digitization, nerve distribution and muscle volume of a human cadaveric soleus muscle were documented and a detailed 3D computer model of neural distribution within the muscle volume was generated. Branching patterns demonstrated divisions that parallel architectural partitions within the soleus; that is, into anterior, posterior, and marginal soleus. Additionally, branching patterns demonstrated further partitioning of the posterior soleus into five distinct regions and the anterior soleus into two regions. Communication between nerve branches of the five regions of posterior soleus and between the anterior and posterior soleus were recorded. Knowledge of these anatomical partitions and their interaction is important as it will aid in the development of functional muscle models and in the understanding of normal and pathological muscle function.