Percutaneous Auricular Nerve Stimulation (Neuromodulation) for Analgesia and Opioid-Sparing Following Knee and Hip Arthroplasty: A Proof-of-Concept Case Series.

We present a case series to demonstrate proof-of-concept for the off-label use of an auricular neuromodulation device-originally developed to treat symptoms associated with opioid withdrawal-to instead provide analgesia and opioid-sparing following knee and hip arthroplasties. Within the recovery room, an auricular neuromodulation device (near-field stimulator system 2 [NSS-2] Bridge, Masimo) was applied to 5 patients. Average daily pain at rest and while moving was a median of 0 to 2 as measured on the 0 to 10 numeric rating scale, while median daily oxycodone use was 0 to 2.5 mg until device removal at home on postoperative day 5. One patient avoided opioid use entirely.

A Randomized Controlled Pilot Study Using Ultrasound-Guided Percutaneous Cryoneurolysis of the Infrapatellar Branch of the Saphenous Nerve for Analgesia Following Total Knee Arthroplasty.

INTRODUCTION: Total knee arthroplasty (TKA) is frequently associated with severe, prolonged postsurgical pain, and therefore local anesthetic-based peripheral nerve blocks are commonly used for postoperative analgesia. Cryoneurolysis involves the use of freezing temperatures to provide a reversible sensory (and motor) block with a duration measured in weeks and months, more commensurate with the typical period of post-TKA pain. We therefore conducted a randomized controlled pilot study to evaluate the use of this modality for the treatment of pain following TKA to (1) determine the feasibility of and optimize the study protocol for a subsequent definitive clinical trial; and (2) estimate analgesia and opioid reduction within the first 3 postoperative weeks. METHODS: A convenience sample of 16 patients undergoing primary TKA with a single-injection and/or continuous adductor canal nerve block were randomized to receive either active cryoneurolysis or a sham procedure targeting the infrapatellar branch of the saphenous nerve, in a participant-masked fashion. This was a pilot study with a relatively small number of participants, and therefore resulting data were not analyzed statistically. RESULTS: Compared with participants receiving sham, the active treatment group reported slightly lower average and worst pain scores as well as opioid consumption and sleep disturbances due to pain at a majority of postoperative time points between postoperative days (POD) 4-21. CONCLUSIONS: Preoperative ultrasound-guided cryoneurolysis of the infrapatellar branch of the saphenous nerve is feasible and may provide analgesic benefits for multiple weeks following TKA. A definitive randomized controlled trial appears warranted.

Percutaneous auricular nerve stimulation (neuromodulation) for the treatment of pain: A proof-of-concept case report using total joint arthroplasty as a surrogate for battlefield trauma.

BACKGROUND: There are few effective pain treatments following trauma on the battlefield other than opioids, which are limited by respiratory depression. Ultrasound-guided percutaneous peripheral nerve stimulation ("neuromodulation") has been proposed as an analgesic, but requires physician-level skills, advanced equipment, and an hour to administer. In contrast, percutaneous auricular neuromodulation may be placed by a medic in the field under nonsterile conditions in a few minutes, theoretically provides analgesia for any anatomic location, has no side effects, and no significant risks. It therefore offers the potential to be applied quickly on the battlefield without any of the limitations of opioids. We propose total joint replacement as a surrogate for battlefield trauma and here present a case report to demonstrate proof of concept. METHODS: Following open total knee or hip arthroplasty under spinal anesthesia, two patients had an auricular neuromodulation device applied within the recovery room. Patients were discharged with the unit and contacted daily for 7 days. RESULTS: The devices were each applied in under 3 minutes without difficulty, were well tolerated during use, and removed without complication at home on Day 5. During use, neither patient experienced pain while lying, sitting, or ambulating. Neither required analgesics other than scheduled celecoxib; and a single tablet (50 mg) of tramadol for one patient on postoperative Days 3 and 4 for pain while lowering herself to a seated position. On Days 6 and 7, both patients experienced an increase in pain, one of whom required around-the-clock tramadol. CONCLUSION: Ambulatory postoperative percutaneous auricular neuromodulation is feasible. In these two cases, it appears to have markedly reduced pain scores and opioid requirements free of systemic side effects during the week following major orthopedic surgery. Considering the potential of this modality to treat trauma on the battlefield without systemic side effects, additional investigation appears warranted. LEVEL OF EVIDENCE: Therapeutic/care management; Level V.

EXpectation Propagation LOgistic REgRession on permissioned blockCHAIN (ExplorerChain): decentralized online healthcare/genomics predictive model learning.

OBJECTIVE: Predicting patient outcomes using healthcare/genomics data is an increasingly popular/important area. However, some diseases are rare and require data from multiple institutions to construct generalizable models. To address institutional data protection policies, many distributed methods keep the data locally but rely on a central server for coordination, which introduces risks such as a single point of failure. We focus on providing an alternative based on a decentralized approach. We introduce the idea using blockchain technology for this purpose, with a brief description of its own potential advantages/disadvantages. MATERIALS AND METHODS: We explain how our proposed EXpectation Propagation LOgistic REgRession on Permissioned blockCHAIN (ExplorerChain) can achieve the same results when compared to a distributed model that uses a central server on 3 healthcare/genomic datasets, and what trade-offs need to be considered when using centralized/decentralized methods. We explain how the use of blockchain technology can help decrease some of the problems encountered in decentralized methods. RESULTS: We showed that the discrimination power of ExplorerChain can be statistically similar to its counterpart central server-based algorithm. While ExplorerChain inherited some benefits of blockchain, it had a small increased running time. DISCUSSION: ExplorerChain has the same prerequisites as a distributed model with a centralized server for coordination. In a manner similar to secure multi-party computation strategies, it assumes that participating institutions are honest, but "curious." CONCLUSION: When evaluated on relatively small datasets, results suggest that ExplorerChain, which combines artificial intelligence and blockchain technologies, performs as well as a central server-based method, and may avoid some risks at the cost of efficiency.

The Relationship Between Apical Vertebral Rotation and Truncal Rotation in Adolescent Idiopathic Scoliosis Using 3D Reconstructions.

STUDY DESIGN: Retrospective review of prospective data. OBJECTIVES: To evaluate the relationship between absolute apical vertebral rotation (AVR) evaluated with upright 3D imaging and angle of trunk rotation (ATR) before and after surgery for thoracic and lumbar curves in adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: New imaging technology allows for improved radiographic assessment of the degree of AVR pre- and postoperatively through 3D spine models created from biplanar, simultaneous spine radiographs. METHODS: A prospective registry was queried and identified 55 AIS patients with major thoracic or major thoracolumbar/lumbar curves who underwent posterior spinal fusion. All patients had biplanar upright imaging of their spine and ATR measurements assessed via scoliometer pre- and postoperatively. RESULTS: There were 33 major thoracic and 22 major lumbar curves. The mean Cobb angles for thoracic and thoracolumbar/lumbar curves were 54° ± 10° and 47° ± 8° preoperatively, and 11 ± 6° and 12 ± 7° postoperatively. The differences in the mean preoperative ATR measurements for both major curve types was not statistically significant; however, the difference in AVR between thoracic curves (13 ± 6°) and lumbar curves (22 ± 7°) was significant (p < .001). There was a significant decrease in the ATR and AVR for both thoracic and thoracolumbar/lumbar curves (p < .001) postoperatively. A significant correlation between ATR and AVR was found only for the major thoracolumbar/lumbar curves (p < .001). The relationship between ATR and AVR changes for both curves was not statistically significant. CONCLUSION: ATR measured via scoliometer strongly correlates with 3D measurements of AVR in both thoracic and lumbar curves before and after surgery for AIS. No significant relationship was found between the changes in ATR and AVR due to surgery. Postoperatively, greater clinical rotational deformity remains in the thoracic spine compared to the lumbar spine, despite greater apical vertebra axial plane correction in thoracic curves. LEVEL OF EVIDENCE: Level II, diagnostic.

Intraoperative Comparison of Measured Resection and Gap Balancing Using a Force Sensor: A Prospective, Randomized Controlled Trial.

BACKGROUND: For establishing femoral component position, gap-balancing (GB) and measured resection (MR) techniques were compared using a force sensor. METHODS: Ninety-one patients were randomized to undergo primary total knee arthroplasty using either MR (n = 43) or GB (n = 48) technique using a single total knee arthroplasty design. GB was performed with an instrumented tensioner. Force sensor data were obtained before the final implantation. RESULTS: GB resulted in greater range of femoral component rotation vs MR (1.5° ± 2.9° vs 3.1° ± 0.5°, P < .05) and posterior condylar cut thickness medially (10.2 ± 2.0 mm vs 9.0 ± 1.3 mm) and laterally (8.5 ± 1.9 mm vs 6.4 ± 1.0 mm). Force sensor data showed a decreased intercompartmental force difference at full flexion in GB (.8 ± 2.3 vs 2.0 ± 3.3u, 1u ≈ 15 N, P < .05). CONCLUSION: GB resulted in a greater range of femoral component rotation and thicker posterior condylar cuts resulting in an increased flexion space relative to MR. Intercompartmental force difference trended toward a more uniform distribution between full extension and full flexion in the GB vs MR group.

Impact of Femoral Stem Design on Failure After Anterior Approach Total Hip Arthroplasty.

BACKGROUND: An increased rate of complications related to femoral component failure has been described with less invasive total hip arthroplasty (THA). This study evaluated the incidence of femoral complications associated with the direct anterior approach for THA. METHODS: Retrospective review was performed of the initial 1120 consecutive patients who underwent direct anterior THA by 2 surgeons. RESULTS: A total of 899 patients (80.3%) had a 2-year follow-up (range, 2-8 years). Complications within 90 days occurred in 20 patients (1.8%): 10 calcar fractures, 1 greater trochanter fracture, 1 canal perforation, 3 hematomas, 2 dislocations, 2 superficial, and 1 deep infection. Nine patients (1%) underwent revision: 5 for aseptic femoral loosening (0.55%), 1 for periprosthetic joint infection, 1 for dislocation, 1 for hip flexor irritation, and 1 for a damaged polyethylene liner. Of the 5 patients with aseptic femoral loosening, 3 had a short, mediolateral tapered stem, 1 cemented stem, and 1 S-ROM stem placed to bypass a canal perforation. There were no revisions for aseptic loosening in the collared, fully hydroxyapatite (HA)-coated compaction broached or triple tapered proximal fit and fill stem designs (70.6% of all stems). Revision rate for femoral loosening was significantly higher for tapered wedge over HA-coated, compaction broached stems (P < .005). CONCLUSION: Pain and function improved predictably with a 0.55% rate of femoral loosening at 2-year follow-up. Among collared, fully HA-coated and triple taper fit and fill femoral stems, there were no instances of revision for aseptic loosening vs 3 in the short stem, collarless mediolateral tapered group.

Comparison of the iAssist Handheld Guidance System to Conventional Instruments for Mechanical Axis Restoration in Total Knee Arthroplasty.

BACKGROUND: Recent advances in total knee arthroplasty (TKA) include an intelligent instrument system designed to provide intraoperative guidance to reduce mechanical alignment errors. Internal position-sensing technology is integrated into microelectronic pods that attach to cutting blocks. The purpose of this prospective, randomized study was to determine whether this iAssist system enables the surgeon to make more accurate bone resections and better restore the mechanical axis compared to conventional instruments in TKA. METHODS: We randomized patients undergoing TKA into 2 groups. Group I (n = 25) underwent TKA assisted by the iAssist guidance system, group II (n = 25) underwent TKA using conventional instruments. Preoperative and postoperative mechanical axes were measured from full-length lower extremity radiographs to evaluate alignment. Additional surgical parameters were also assessed, including tourniquet time and blood loss. RESULTS: Patient demographics and preoperative mechanical axis alignments were similar between the groups. Postoperatively, 4.0% of patients had greater than 3° of tibial or femoral component mal-alignment in the guidance-assisted cohort, compared with 36.0% in the conventional group (P < .05). Additionally, group I showed significant improvement in variance seen in both the femoral mechanical axis (1.65° ± 0.17° vs 2.23° ± 0.33°, P < .005) and tibial mechanical axis (1.28° ± 0.13° vs 1.71° ± 0.24°, P < .005) compared to group II. There were no significant differences in tourniquet time (P = .86) or blood loss (P = .39) between groups. CONCLUSION: Use of the iAssist system in TKA results in an improved postoperative mechanical axis and decreased alignment variability compared to conventional instruments, without significantly increasing operative time.

Avoiding Anomalous Tendon Harvest at the Pes Anserinus Insertion.

The purpose of this study was to identify the frequency and characteristics of anomalous pes anserinus tendon morphology in an adolescent population undergoing knee anterior cruciate ligament (ACL) reconstruction surgery. The records of all children who underwent ACL reconstruction surgery at our tertiary care children's hospital from June 2008 through February 2012 were reviewed. Operative reports were reviewed for any indication that an anomaly existed in the pes anserinus or that there was difficulty harvesting the required tendons. Magnetic resonance imaging (MRI) studies were then reviewed for these patients looking for evidence of any anomaly within the pes anserinus structures. Retrospective review was performed on 123 children (mean age, 16.1 years). Three girls (mean age, 16.2 years) were identified as having a low-lying muscle belly and accessory tendon when attempting to harvest the gracilis tendon. Proximal exploration of this short tendon conjoining the gracilis insertion revealed a muscle belly approximately 5 cm from its insertion in the pes anserinus. This anomaly was present in 2.4% of the cases. Based on previous literature, the anomalous muscle present in our cohort could be sartorius or semimembranosus. MRI analysis suggests that the accessory muscle and tendon could be an aberrant strip of the semimembranosus tendon, an anomalous tendon and muscle belly of the gracilis, or a thickening and separation of the sartorius tendon. Anomalous pes anserinus tendons were found to exist in 2.4% of our adolescent study population. At the time of surgery, if a tendon is harvested with a very low-lying muscle belly (with less than 6 cm of tendon), then the presence of an aberrant tendon should be considered. Preoperative MRI may provide evidence of an anomalous tendon if that information is sought.

The 15-Year Evolution of the Thoracoscopic Anterior Release: Does It Still Have a Role?

STUDY DESIGN: Retrospective. PURPOSE: To determine how the indications for anterior thoracoscopic release and fusion have evolved over time. OVERVIEW OF LITERATURE: Anterior release was commonly performed to correct severe spinal deformities before the advent of pedicle screw fixation. The thoracoscopic approach significantly reduced the morbidity, as compared to open thoracotomy procedures. METHODS: We reviewed charts and radiographs of pediatric spinal deformity patients who underwent thoracoscopic release/fusion for their deformity from 1994 to 2008. Indications for the thoracoscopic procedure were assigned to one of the following categories: hyperkyphosis, large/stiff scoliosis, crankshaft prevention, and 'other'. We analysed indications grouped in 3-year intervals to determine how the indications for this procedure evolved over the past 15 years. RESULTS: One hundred and thirty-eight patients (mean age, 15 years; range, 2-28 years) underwent the procedure, with 160 identified indications. The frequency of thoracoscopic anterior release/fusion decreased after peaking in the years 2000-2002. Initially, hyperkyphosis was the most frequent indication (15/33, 45%; 1994-1996), but declined to an intermittent indication since 2006. The use of thoracoscopy to prevent crankshaft has also declined, but remains an indication for the most immature cases (2/17, 12%; 2006-2008). Severe or rigid scoliosis is currently the most common indication for thoracoscopic release/fusion at our center (11/17, 65%; 2006-2008). CONCLUSIONS: The indications for a thoracoscopic anterior release/fusion has evolved with our increased understanding of this procedure and improved posterior fixation with pedicle screw instrumentation. Thoracoscopy in select spinal deformity patients still has an important role despite its less frequent use, as compared to the past decade.

Generation of a Patient-Specific Model of Normal Sagittal Alignment of the Spine.

STUDY DESIGN: Mathematical modeling of normal sagittal spinal alignment. OBJECTIVE: To create a patient specific 3-dimensional (3D) model of normal adolescent spinal shape and alignment. SUMMARY OF BACKGROUND DATA: Recreating normal sagittal balance is a key goal in spinal deformity surgery. Because of the variation in normal sagittal alignment based on inherent pelvic parameters, it is difficult to know what is normal for a given patient who presents with spinal deformity. METHODS: Simultaneous biplanar 2-dimensional digital radiographs were taken for pediatric patients with no known spinal disease using the EOS system. Three-dimensional reconstructions were produced using sterEOS and imported into custom MATLAB software. The researchers defined relationships to approximate orientations and positions of the vertebral bodies from patients' pelvic incidence (PI). The predicted spinal contour was then calculated to optimize congruence to patients' sagittal T1-sacrum offset, sagittal curve inflection point location, and predicted vertebral body orientations and positions. RESULTS: A total of 75 patients (26 male and 49 female) were included, mean age 14.5 ± 2.6 years. Baseline measurements were PI 46.7° ± 10.2°, sacral lope 40.2° ± 8.9°, T1-T12 kyphosis 39.8° ± 8.8°, and L1-L5 lordosis -37.1° ± 11.2°. Average difference in vertebral position in the anteroposterior direction between actual spines and their predicted models was 1.2 ± 1.2 mm and varied from an absolute minimum of 0.2 mm (T3) to an absolute maximum of 3.7 mm (L2). CONCLUSIONS: This model uses an adolescent patient's PI to predict the normal sagittal alignment that best matches that patient's native sagittal curve. The model was validated on patients with no spinal deformity; average difference between actual sagittal positions of each vertebra and those predicted by the model was less than 5 mm at each vertebral level. This model may be useful in adolescent scoliotic patients with altered sagittal alignment to determine the magnitude of 3D deformity (compared with predicted normal values) and the completeness of 3D correction.

Lateral center-edge angle on conventional radiography and computed tomography.

BACKGROUND: Lateral center-edge angle (LCEA), originally described and validated on AP radiographs, has been used increasingly in CT-based studies, but it is unclear whether the measure is reliable and whether it correlates with that on AP radiographs. QUESTION/PURPOSES: We therefore determined: (1) the interobserver and intraobserver reliabilities of the LCEA measured on AP radiographs; (2) the interobserver and intraobserver reliabilities of the LCEA measured on CT scans; and (3) the intermodality correlation of the LCEA between CT and AP radiography. METHODS: We reviewed the AP radiographs and CT scans of 22 patients treated for slipped capital femoral epiphyses. CT scans were reoriented to a neutral pelvic tilt and inclination. Three evaluators measured the LCEA on the unaffected hip on the AP and CT coronal images that corresponded to the center of the acetabulum on the axial slice. RESULTS: We found an interobserver intraclass correlation (ICC) analysis of 0.84 for the AP radiographs and 0.88 for the CT scans. The intraobserver ICC for the AP radiographs was 0.96, and for the CT scans 0.98. The intermodality ICC for the CT scans and AP radiographs was 0.79, with a lower bound of 0.61 and an upper bound of 0.87. CONCLUSIONS: Our data suggest the LCEA measured on a CT scan is reliable and correlates with the LCEA on AP radiographs.

Postoperative changes in spinal rod contour in adolescent idiopathic scoliosis: an in vivo deformation study.

STUDY DESIGN: Prospective case series. OBJECTIVE: To evaluate the change in spinal rod contour from before implantation to after surgical correction of thoracic curves in patients with adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: With segmental pedicle screw spinal instrumentation and vertebral derotation, many authors have reported a loss of thoracic kyphosis postoperatively. Although surgeons anticipate some flattening of the preimplantation rod contour in the sagittal plane, the magnitude of this change in shape has not been documented. METHODS: The concave and convex rod shapes of 5.5-mm ultrahigh-strength steel spinal rods (200 KSI) from patients with thoracic adolescent idiopathic scoliosis (n = 27), which were contoured with benders by the surgeon, were traced prior to insertion. Postoperative (average, 5 weeks) sagittal rod shape was determined from lateral 2-dimensional radiographs. Maximal rod deflection and angle of the tangents to rod end points (Cobb) were measured. Repeated measures analysis of variance assessed differences between pre- and postoperation. RESULTS: The scoliosis of 55° ±14° was corrected 72% to 15° ± 5°. The preinsertion rod shapes were more kyphotic for the concave (45.6°) than for the convex (31.4°) rods. Following correction, the concave rods flattened, with decrease in deflection of 13 mm and reduction in angle of 21° (both P < 0.001). The convex rods increased 1.5 mm in deflection and 2° in angle (P < 0.01, P = 0.18). The sagittal profile was maintained postoperatively as measured from T5-T12: 19° ±14° versus 22° ± 6° (pre vs. post, P > 0.1). CONCLUSION: We found a significant difference between pre- and postoperative rod contour, particularly for concave rods. Rod overcontouring (by ~20° for concave rod) resulted in high degrees of correction without loss of sagittal alignment. The resulting deformations are likely associated with substantial in vivo deforming forces.