John J. Finneran

QUANTIFICATION OF PARTIAL OR COMPLETE A4 PULLEY RELEASE WITH FDP REPAIR IN CADAVERIC TENDONS

PURPOSEnRepair of a lacerated flexor digitorum profundus (FDP) tendon underneath or just distal to the A4 pulley can be technically challenging, and success can be confounded by tendon triggering and scarring to the pulley. The purpose of this study was to quantify the effect of partial and complete A4 pulley release in the context of a lacerated and repaired FDP tendon just distal to the A4 pulley.nnnMETHODSnTendon biomechanics were tested in 6 cadaveric hands secured to a rigid frame, permitting measurement of tendon excursion, tendon force, and finger range of motion. After control testing, each finger had laceration and repair of the FDP tendon at the distal margin of the A4 pulley using a 6-strand core suture technique and epitendinous repair. Testing was then repeated after the following interventions: (1) intact A4 pulley, (2) release of the distal half of the A4 pulley, (3) complete release of the A4 pulley, and (4) continued proximal release of the sheath to the distal edge of A2 (release of C2, A3, and C1 pulleys). Release of the pulleys was performed by incision; no tissue was removed from the specimens.nnnRESULTSnFrom full extension to full flexion, average FDP tendon excursion for all intact digits was 37.9 ± 1.5 mm, and tendon repair resulted in average tendon shortening of 1.6 ± 0.4 mm. Flexion lag increased from <1 mm to >4 mm with venting of the A4 pulley, complete A4 release, and proximal sheath release, respectively. Compared to the intact state, repair of the tendon with an intact A4 pulley, release of half the A4 pulley, complete A4 release, and proximal sheath release resulted in percentage increases in work of flexion of 11.5 ± 3.1%, 0.83 ± 2.8%, 2.6 ± 2.4%, and 3.25 ± 2.2%, respectively.nnnCONCLUSIONSnAfter FDP laceration and repair in the region of the A4 pulley, work of flexion did not increase by more than 3% from control conditions after partial or complete A4 pulley release, and work of flexion was significantly less than that achieved by performing a repair and leaving the A4 pulley intact.

Mechanical Feasibility of Immediate Mobilization of the Brachioradialis Muscle After Tendon Transfer

PURPOSEnTendon transfer is often used to restore key pinch after cervical spinal cord injury. Current postoperative recommendations include elbow immobilization in a flexed position to protect the brachioradialis-flexor pollicis longus (BR-FPL) repair. The purpose of this study was to measure the BR-FPL tendon tension across a range of wrist and elbow joint angles to determine whether joint motion could cause repair rupture.nnnMETHODSnWe performed BR-to-FPL tendon transfers on fresh-frozen cadaveric arms (n = 8) and instrumented the BR-FPL tendon with a buckle transducer. Arms were ranged at 4 wrist angles from 45 degrees of flexion to 45 degrees of extension and 8 elbow angles from 90 degrees of flexion to full extension, measuring tension across the BR-FPL repair at each angle. Subsequently, the BR-FPL tendon constructs were removed and elongated to failure.nnnRESULTSnOver a wide wrist and elbow range of motion, BR-FPL tendon tension was under 20 N. Two-way analysis of variance with repeated measures revealed a significant effect of wrist joint angle (p<.001) and elbow joint angle (p<.001) with significant interaction between elbow and joint angles (p<.001). Because the failure load of the repair site was 203 +/- 19 N, over 10 times the loads that would be expected to occur at the repair site, our results demonstrate that the repair has a safety factor of at least 10.nnnCONCLUSIONSnOur tendon force measurements support the assertion that the elbow joint need not be immobilized when the BR is used as a donor muscle in tendon transfer to the FPL. This is based on the fact that maximum passive tendon tension was only about 20 N in our cadaveric model and the failure strength of this specific repair was over 200 N. We suggest that it is possible to consider performing multiple tendon transfers in a single stage, avoiding immobilization, which may adversely affect functional recovery. These results must be qualified by the fact that issues unique to living tissues such as postoperative edema and tendon gliding cannot be accounted for by this cadaveric model.

Exchanging a King Laryngeal Tube™ for an endotracheal tube using a fibreoptic bronchoscope−Aintree catheter combination in a known difficult airway

To the Editor, We report a case where a King Laryngeal Tube (LT; King Systems, Noblesville, IN, USA) was exchanged for an endotracheal tube (ETT) using a fibreoptic bronchoscope Aintree intubating catheter (FOB-AIC; Cook Medical Inc, Bloomington, IN, USA) combination in a patient with a proven difficult airway, coexisting neurologic and facial injuries, and massive oral and perioral edema. Consent for this report was given by the next of kin. A 26-year-old male polytrauma patient presented to the emergency department with multiple facial and skull fractures. Additional injuries included subarachnoid hemorrhage, cerebral edema, distal right internal carotid artery dissection, and extensive subcutaneous emphysema possibly secondary to tracheal rupture. Because of difficulty with airway management in the field, the King LT (Figure A) was placed by the emergency medical technicians. The anesthesiology team was consulted to provide definitive airway management. Airway examination revealed multiple lacerations to the face with blood crusted around his ears, nose, and oropharynx. The patient had extensive perioral edema to the extent that the King LT occupied nearly his entire oral cavity, precluding further examination. Because of the severity of the patient’s injuries, removing the King LT or deflating the proximal cuff to perform direct or video laryngoscopy was considered unsafe and technically unlikely to be successful. As such, primary airway assessment with a FOB was deemed appropriate. A bronchoscopy elbow was placed on the proximal end of the King LT and connected to the ventilator to allow continuous positive pressure ventilation (PPV). After administration of rocuronium, a 4.0 mm outer diameter (OD) FOB was advanced through the bronchoscopy elbow and into the ventral ventilation port of the King LT, where further investigation showed a slightly deviated laryngeal opening with open vocal cords and an intact tracheobronchial tree. Based on the above assessment, it was decided that FOB-guided intubation using the AIC with continuous PPV and King LT in situ would be ideal. The AIC was loaded onto the 4.0-mm OD FOB, and the FOB-AIC was advanced through the bronchoscopy elbow and subsequently through the largest ventral fenestration port of the King LT into the trachea (Figure B) while maintaining continuous PPV with FIO2 = 1.0. The FOB was then removed from the AIC (Figure C). The AIC was held in place while the King LT balloons were deflated, and the King LT was removed over the AIC. PPV was briefly interrupted during these maneuvers. Next, an 8.0mm ID ETT was advanced easily over the AIC and into the trachea until the tube was 23 cm at the teeth, and PPV was resumed (Figure 1D). The AIC was then removed from the ETT, and ETT placement was confirmed. Laryngeal tube exchange with FOB-AIC was described by Genzwuerker et al. in a healthy patient population under general anesthesia. The FOB-AIC technique was also shown to be superior to extraluminal techniques of FOB intubation in a mannequin and cadaver study performed by The views expressed in the submitted article are the authors own and not an official position of the institution.

Erector Spinae Plane Blocks Provide Analgesia for Breast and Axillary Surgery: A Series of 3 Cases

tic gel to create the final layer of soft tissue. Ballistic gel is a 12:1 mixture of water and gelatin developed by the military to simulate the density and viscosity of soft tissue (Figs. 1, 2). Our goal was to make this model low cost, easy to fabricate, and available globally. To that end, we published our design files and an instruction manual on Thingiverse, an open-source community Web site for 3D printing. Our 3D thoracic epidural model can be found at https://www.thingiverse. com/thing:1855444. Cost of materials is approximately

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation: Neuromodulation of the Femoral Nerve for Postoperative Analgesia Following Ambulatory Anterior Cruciate Ligament Reconstruction: A Proof of Concept Study: FEMORAL NEUROMODULATION AND POSTOP PAIN

40, and approximate building time is less than 2 days. By comparison, Jeganathan et al describe cost of materials as approximately

Proximal Versus Distal Continuous Adductor Canal Blocks: Does Varying Perineural Catheter Location Influence Analgesia? A Randomized, Subject-Masked, Controlled Clinical Trial

400 and time to develop of “less than 4 days.” This project was completed using a 3D printer and other resources at a university Makerspace. For thosewithout access to a 3D printer, design files can be uploaded to one of several printing hubs and ordered online (https://www.3dhubs.com/). Our regional anesthesia team places approximately 15 to 20 thoracic epidural catheters per week. We use the model to introduce residents to epidural technique at the beginning of their regional anesthesia rotation. We are currently conducting a survey of resident satisfaction with visual and tactile fidelity of the model and its overall usefulness as a teaching tool. Ultrasound fidelity is excellent. We commend Jeganathan et al for their excellent work. Their article describes one of the first projects in what promises to be an exciting wave of educational tools based on 3D printing and computer-aided design. We invite others interested in 3D printing to visit our link, build a model for themselves, and modify the design to fit their practice. We are excited about the open-source nature of this project and the possibility of global collaboration to continually improve it.

Ultrasound-Guided Percutaneous Cryoneurolysis for Acute Pain Management: A Case Report.

The purpose of this prospective proof of concept study was to investigate the feasibility of using percutaneous peripheral nerve stimulation of the femoral nerve to treat pain in the immediate postoperative period following ambulatory anterior cruciate ligament reconstruction with a patellar autograft.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation: Neuromodulation of the Sciatic Nerve for Postoperative Analgesia Following Ambulatory Foot Surgery, a Proof-of-Concept Study.

BACKGROUND: A continuous adductor canal block provides analgesia after surgical procedures of the knee. Recent neuroanatomic descriptions of the thigh and knee led us to speculate that local anesthetic deposited in the distal thigh close to the adductor hiatus would provide superior analgesia compared to a more proximal catheter location. We therefore tested the hypothesis that during a continuous adductor canal nerve block, postoperative analgesia would be improved by placing the perineural catheter tip 2–3 cm cephalad to where the femoral artery descends posteriorly to the adductor hiatus (distal location) compared to a more proximal location at the midpoint between the anterior superior iliac spine and the superior border of the patella (proximal location). METHODS: Preoperatively, subjects undergoing total knee arthroplasty received an ultrasound-guided perineural catheter inserted either in the proximal or distal location within the adductor canal in a randomized, subject-masked fashion. Subjects received a single injection of lidocaine 2% via the catheter preoperatively, followed by an infusion of ropivacaine 0.2% (8 mL/h basal, 4 mL bolus, 30 minutes lockout) for the study duration. After joint closure, the surgeon infiltrated the entire joint using 30 mL of ropivacaine (0.5%), ketorolac (30 mg), epinephrine (5 &mgr;g/mL), and tranexamic acid (2 g). The primary end point was the median level of pain as measured on a numeric rating scale (NRS) during the time period of 8:00 AM to 12:00 PM the day after surgery. RESULTS: For the primary end point, the NRS of subjects with a catheter inserted at the proximal location (n = 24) was a median (10th, 25th–75th, 90th quartiles) of 0.5 (0.0, 0.0–3.2, 5.0) vs 3.0 (0.0, 2.0–5.4, 7.8) for subjects with a catheter inserted in the distal location (n = 26; P = .011). Median and maximum NRSs were lower in the proximal group at all other time points, but these differences did not reach statistical significance. There were no clinically relevant or statistically significant differences between the treatment groups for any other secondary end point, including opioid consumption and ambulation distance. CONCLUSIONS: For continuous adductor canal blocks accompanied by intraoperative periarticular local anesthetic infiltration, analgesia the day after knee arthroplasty is improved with a catheter inserted at the level of the midpoint between the anterior superior iliac spine and the superior border of the patella compared with a more distal insertion closer to the adductor hiatus.