Robotic-assisted total knee arthroplasty reduces soft-tissue releases which improves functional outcomes: A retrospective study.

BACKGROUND: There is increasing use of Robotic-Assisted (RA) and personalized alignment techniques in total knee arthroplasty (TKA). The hypothesis of this study was that RA TKA would result in fewer soft-tissue releases, and that fewer soft-tissue releases would be associated with improved clinical outcomes. METHODS: A retrospective review of an internal company registry was conducted for all primary TKAs performed from Jan 1, 2014, through a database extract date of Nov 4, 2022. These were grouped by whether there was an intentional soft-tissue release performed (STR) during the surgery or not (NSTR) and whether RA was utilized. The incidence of STR was compared between RA-TKAs and those performed with manual instrumentation. Knee Society Score (KSS) and Knee Society Function Scores (KSFS) were collected at 6 months, 1 year and 2 years. Kaplan-Meier survivorship was performed. RESULTS: The incidence of STR was significantly lower for RA vs. Manual (43.81% Vs 86.62%, p < 0.0001). The TKAs with NSTR had higher KSFS compared to those with STR at 6 months (84.73 Vs. 77.51, p < 0.0001), 1 year (89.87 Vs. 83.54, p < 0.0001) and 2 years (90.09 Vs. 82.65, p < 0.0001). There was no difference in survivorship, or KSS at any time point. However, the NSTR group had improved KSS pain sub score at 2 years. CONCLUSION: The results of this observational, retrospective analysis found that the incidence of soft-tissue release was lower with RA-TKA. Further, regardless of if RA was used, avoiding releases was associated with improved KSFS and KSS pain scores through 2 years post-operatively.

The Role of Endoscopic Assistance in Surgery for Pediatric Cholesteatoma in Reducing Residual and Recurrent Disease.

The primary aim of this study was to evaluate long-term recurrent and residual disease after surgery for acquired cholesteatoma in children according to surgical approach. A total of 71 interventions performed on 67 pediatric patients were included in the study. Canal wall-up tympanomastoidectomy (CWUT) was performed in 31 ears (13 with endoscopic assistance), a transcanal esclusive endoscopic approach (TEEA) was used in 22, and canal wall-down tympanomastoidectomy (CWDT) was performed in 18. Overall, the cholesteatoma relapse rate estimated by the Kaplan-Meier method was 47 ± 6% at 12 years; the recurrent cholesteatoma rate was 28 ± 6% and the residual cholesteatoma rate was 26 ± 5%. The relapse rate according to surgical approach was 33 ± 11% for CWDT, 60 ± 9% for CWUT, and 40 ± 11% for TEEA (p = 0.04). The difference for recurrent disease was no recurrent disease for CWDT, 42 ± 9% for CWUT, and 32 ± 11% for TEEA (p = 0.01). The residual disease rate was significantly reduced with endoscopy: 42 ± 8% without endoscopy vs. 9 ± 5% with (p = 0.003). CWDT can still be considered in primary surgery in case of extensive cholesteatomas and small mastoid with poor pneumatization. TEEA can be recommended for small cholesteatoma not extending to the mastoid to reduce morbidity. Endoscopic assistance seems useful to reduce residual disease in CWUT, whereas it does not have a significant impact on preventing recurrent disease.

Vascularized Fibular Epiphyseal Transfer for Pediatric Limb Salvage: Review of Applications and Outcomes.

Vascularized fibular epiphyseal transfer (VFET) offers a functional advantage in pediatric limb salvage due to the preservation of growth potential and an articular surface for remodeling. This review summarizes the available evidence on the clinical characteristics and outcomes of pediatric reconstruction applying VFET at different recipient sites and with varying techniques. VFET was used to reconstruct the proximal humerus, distal radius or ulna, proximal femur, distal fibula, calcaneus, and mandible. Although most often harvested on the anterior tibial artery, VFET has also been performed using the peroneal artery, the inferior lateral genicular artery, and a dual pedicle. Recipient site flap inset most often involved fixation with plates and/or screws as well as soft tissue reconstruction using a retained slip of biceps femoris tendon. Outcomes included limb growth, range of motion, and strength. The most common reported complications were bone flap fracture and peroneal nerve palsy. The anterior tibial artery was the most applied pedicle with reliable limb growth, but with the added risk of postoperative peroneal palsy. Bone flap fracture most often occurred at the proximal humerus and femur recipient sites. Plate fixation and the combined use of allograft had lower instances of bone flap fracture. This review highlights how the anticipated dynamic growth and remodeling this free flap offers in the long term must be weighed against its complexity and potential complications.

Retained Functional Antibiotic Hip Spacers Have High Rates of Stem Loosening, Subsidence, and Reoperation.

BACKGROUND: Functional antibiotic hip spacers for treatment of periprosthetic joint infection may be retained in patients deemed too sick for reimplantation, or who elect to forego additional surgery. Our aim was to characterize reoperations, modes of failure, and function outcomes in patients who have retained hip spacers. METHODS: We performed a retrospective review of 43 hips that underwent placement of an articulating hip spacer between January 1, 2014 and November 30, 2021. There were 28 hips that completed 2-stage exchange (TS group) and were reimplanted at mean 4 months (range, 2 to 10). The other 15 hips underwent planned spacer retention (RS group). Mean follow-up was 2.9 years (range, 1 to 6.1 years). The RS group was older (74 versus 66 years, P = .005) and had a higher age-adjusted Charlson Comorbidity Index (4.4 versus 3.3, P = .04) compared with the TS group. RESULTS: Overall survivorship free of reinfection was 91% at 1 year and 86% at 5 years. There were 6 RS hips that underwent reimplantation for spacer failure at a mean of 23 months (range, 6 to 71 months) and 8 had radiographic stem loosening/subsidence. Patients who had a retained spacer at final follow-up were more likely to require a walker (P = .005) or wheelchair (P = .049) compared with patients who underwent reimplantation. CONCLUSIONS: Retained hip spacers can decrease overall surgical burden, but are associated with high rates of stem loosening, subsidence, and unplanned reoperation. Planned spacer retention should be undertaken with caution in patients healthy enough to undergo reimplantation.

Conversion Total Hip Arthroplasty in the Era of Bundled Care Payments: Impacts on Costs of Care.

BACKGROUND: Conversion hip arthroplasty is defined as a patient who has had prior open or arthroscopic hip surgery with or without retained hardware that is removed and replaced with arthroplasty components. Currently, it is classified under the same diagnosis-related group as primary total hip arthroplasty (THA); however, it frequently requires a higher cost of care. METHODS: A retrospective study of 228 conversion THA procedures in an orthopaedic specialty hospital was performed. Propensity score matching was used to compare the study group to a cohort of 510 primary THA patients by age, body mass index, sex, and American Society of Anesthesiologists score. These matched groups were compared based on total costs, implants used, operative times, length of stay (LOS), readmissions, and complications. RESULTS: Conversion THA incurred 25% more mean total costs compared to primary THA (P < .05), longer lengths of surgery (154 versus 122 minutes), and hospital LOS (2.1 versus 1.56 days). A subgroup analysis showed a 57% increased cost for cephalomedullary nail conversion, 34% increased cost for sliding hip screw, 33% for acetabular open reduction and internal fixation conversion, and 10% increased costs in closed reduction and percutaneous pinning conversions (all P < .05). There were 5 intraoperative complications in the conversion group versus none in the primary THA group (P < .01), with no statistically significant difference in readmissions. CONCLUSION: Conversion THA is significantly more costly than primary THA and has longer surgical times and greater LOS. Specifically, conversion THA with retained implants had the greatest impact on cost.

Osteoneogenesis at the Round Window: A Possible Cause of Cochlear Implant Failure?

Surgery for cochlear implant is a traumatic procedure, with inflammatory responses leading to immediate and delayed intracochlear changes, resulting in newly formed fibrous and bony tissue. This newly formed tissue is thought to affect speech perception with cochlear implants and can also play a role in causing device malfunctioning and soft failures. We present a case of left cochlear implant explantation and reimplantation in a 15-year-old girl, who experienced deterioration of speech perception and device failure associated with osteoneogenesis of the round window, which could represent a cause of cochlear implant failure. To avoid surgical trauma of the cochlear lateral wall, enlarged round window insertion rather than a cochleostomy, soft surgical techniques, and the application of steroids are all important issues to prevent new tissue formation, although special attention should also be given to the trauma of round window borders.

Endoscopic transcanal tympanoplasty type I in children: Evolving experience in tragus perichondrium vs. acellular porcine small intestinal sub-mucosa grafts.

OBJECTIVES: Endoscopic trans-canal tympanoplasty type I (ETT) is gradually diffusing worldwide. It mainly allows less invasive surgery in children with respect to a microscope approach by avoiding post-auricular access. The aim of this study is to illustrate our experience in endoscopic reconstruction of tympanic membrane, using autologous tragus perichondrium (TP) and non-autologous acellular porcine small intestinal sub-mucosa (SIS) as grafts. METHODS: Between January 2011 and December 2020, the results of a prospective non-randomized series of consecutive ETT were analyzed. The primary outcome was closure rate at 6 months and secondary outcomes are closure rates associated with age, size of perforation, type of perforation and middle ear status, presence of myringosclerosis, type of graft, status of contralateral ear, adenoidectomy and pre-postoperative ABG change. Statistical analysis was performed using the SPSS statistical package. RESULTS: One hundred and sixteen consecutive procedures, mean age 9.4 years (range 4-17 years), were evaluated. TP and SIS grafts were used in 65 (56%) and 51 (44%) procedures, respectively. Mean duration of surgical procedure was 53 ± 21 min for SIS and 77 ± 18 min for TP (P = 0.001) Total graft intake was 82.8%; TP and SIS intake were 86.2% and 78.4% (P = 0.3), respectively. Graft intake w.r.t. in age stratified age groups was not statistically significant. Average preoperative and postoperative air-bone gap was 12.1 ± 7.6 dB and 5.5 ± 3.8 dB, respectively (P = 0.001). The difference in closure rates was not significant. Neither intra- nor postoperative complications were observed. CONCLUSIONS: In children, ETT is an applicable and less invasive technique compared to the microscope and offers less morbidity. The use of SIS contributes additional less invasiveness to endoscopic surgery by avoiding tragus harvesting with a comparable success rate and granting significantly less surgical duration.

Long-Term Lateral Semicircular Canal Function in Children with Cochlear Implants: Results of Video Head Impulse Test.

In children with profound deafness, bilateral cochlear implant (CI) is an effective, established procedure. However, its safety on vestibular function has recently been debated. The goal of this study is to evaluate the long-term lateral semicircular canal high-frequency vestibulo-oculomotor reflex (LSC HF VOR) in children with CI by video head impulse testing (vHIT). This is a cross-sectional study assessing a cohort of children who received either a unilateral (12) or a bilateral (12) cochlear implant (CI), compared with a control group of 12 normal-hearing children. No significant LSC HF VOR gain difference was found between CI users and controls. In the unilaterally implanted group, the LSC HF VOR gain measured in the "CI-ON" condition was significantly higher than in the "CI-OFF" condition, both in the implanted and in the non-implanted ear. In the bilaterally implanted group, the difference between the two conditions was not significant. Our results do not show any impairment of LSC HF VOR function in children with CI compared to normal-hearing children in the long-term period. This suggests that both unilateral and simultaneous/sequential bilateral CI are procedures that do not impair HF LSC long-term function when analyzed by vHIT.

Cognitive improvement after cochlear implantation in deaf children with associated disabilities.

AIM: To monitor functional auditory and non-verbal cognitive skills in children with cochlear implants who had associated disabilities over a 24-month period and define how cochlear implantation may impact on non-verbal cognition by restoring functional auditory skills. METHOD: Sixty-four children with cochlear implants (36 females, 28 males; mean age 4y 3mo, SD 3y 5mo, 9mo-14y 5mo) were recruited and divided into three groups: children with typical development group (TDG); children with associated disabilities not linked to non-verbal cognitive disorders group (ADG1); and children with associated disabilities linked to non-verbal cognitive disorders group (ADG2). Tests of functional auditory, communicative, and non-verbal cognitive skills were performed before cochlear implantation and at 12 and 24 months after cochlear implantation. RESULTS: Functional auditory and communicative skills improved similarly in the three groups at 12 and 24 months after implantation. An increase in non-verbal cognitive scores was present in children in the ADG2 from baseline to 12 and 24 months (p<0.01), whereas scores remained stable in children in the TDG and ADG1. The increased functional auditory skills scores after cochlear implantation corresponded to an increase in non-verbal cognitive scores (p=0.032) in children in the ADG2. INTERPRETATION: Children with associated disabilities, especially if linked to non-verbal cognitive disorders, benefitted from cochlear implantation. They improved their comprehension of acoustic information inferred from the environment, improving not only functional auditory skills but also non-verbal cognition.

Opioid Use After Discharge Following Primary Unilateral Total Knee Arthroplasty: How Much Are We Over-Prescribing?

BACKGROUND: The opioid crisis pressures orthopedic surgeons to reduce the amount of narcotics prescribed for post-operative pain management. This study sought to quantify post-operative opioid use after hospital discharge for primary unilateral total knee arthroplasty (TKA) patients. METHODS: A prospective cohort of primary unilateral TKA patients performed by one of 5 senior fellowship-trained arthroplasty surgeons were enrolled at a single institution. Detailed pain journals tracked all prescriptions and over-the-counter pain medications, quantities, frequencies, and visual analog scale pain scores. Narcotic and narcotic-like pain medications were converted to morphine milligram equivalents (MME). Statistical analysis was performed using Student's t-test with α < 0.05. RESULTS: Data from 89 subjects were analyzed; the average visual analog scale pain score was 6.92 while taking narcotics. The average number of days taking narcotics was 16.8 days. The distribution of days taking narcotics was right shifted with 52.8% of patients off narcotics after 2 week, and 74.2% off by 3 weeks post-op. The average MME prescribed was significantly greater than MME taken (866.6 vs 428.2, P < .0001). The average number of narcotic pills prescribed was significantly greater than narcotic pills taken (105.1 vs 52.0, P < .0001). The average excess narcotic pills prescribed per patient was 53.1 pills. About 48.3% took fewer than 40 narcotic pills; 75.3% took fewer than 75 narcotic pills. About 3.4% did not require any narcotics; 40.5% required a refill of narcotics. Also, 9.0% went home the day of surgery. CONCLUSION: Significantly more narcotics were prescribed than were taken in the post-operative period following TKA with an average 53.1 excess narcotic pills per patient. Adjusting prescribing patterns to match patient narcotic usage could reduce the excess narcotic pills following TKA.

Use of Tetrahydrocannabinol and Cannabidiol Products in the Perioperative Period Around Primary Unilateral Total Hip and Knee Arthroplasty.

BACKGROUND: Given the opioid crisis in America, patients are trying alternative medications including tetrahydrocannabinol (THC) and other cannabidiol (CBD) containing products in the perioperative period, especially in states where these products are legal. This study sought to analyze usage rates of CBD/THC products in the perioperative period for primary unilateral total hip and knee arthroplasty (THA/TKA) patients and identify a possible association with post-operative opioid use. METHODS: A prospective cohort of primary unilateral THA/TKA patients were enrolled at a single institution. Patients who completed detailed pain journals were retrospectively surveyed for CBD/THC product usage. Pain medications were converted to morphine milligram equivalents (MME). RESULTS: Data from 195 of the 210 patients (92.9% response rate) following primary arthroplasty were analyzed. Overall, 16.4% of arthroplasty-22.6% (n = 19) of TKA and 11.7% (n = 13) of THA-patients used CBD/THC products in the perioperative period. There was a wide variety of usage patterns among those using CBD/THC products. In comparing CBD/THC users and non-users, there was no significant difference in the length of narcotic use, total morphine milligram equivalents taken, narcotic pills taken, average post-op pain scores, the percentage of patients requiring a refill of narcotics, or length of stay. CONCLUSION: Understanding that CBD/THC usage was not consistent for patients who used these products, 22.6% of TKA and 11.7% of THA patients tried CBD/THC products in the perioperative period. In this small sample, CBD/THC use was not associated with a major effect on narcotic requirements. Further studies on the effects of CBD/THC are needed as these therapies become more widely available.

Opioid Use After Discharge Following Primary Unilateral Total Hip Arthroplasty: How Much Are We Overprescribing?

BACKGROUND: The opioid crisis pressures orthopedic surgeons to reduce the amount of narcotics prescribed for postoperative pain management. This study sought to quantify postoperative opioid use after hospital discharge for primary unilateral total hip arthroplasty (THA) patients. METHODS: A prospective cohort of primary unilateral THA patients were enrolled at a single institution. Detailed pain journals tracked all prescription and over-the-counter pain medication, quantity, frequency, and visual analog scale pain scores. Pain medications were converted to morphine milligram equivalents (MME). RESULTS: Data from 121 subjects were analyzed; the average visual analog scale pain score was 3.44 while taking narcotics. The average number of days taking narcotics was 8.46 days. The distribution of days taking narcotics was right shifted with 50.5% of patients off narcotics after 1 week, and 82.6% off by 2 weeks postoperatively. The average number of narcotic pills prescribed was significantly greater than narcotic pills taken (72.5 vs 28.8, P < .0001). The average MME prescribed was significantly greater than MME taken (452.1 vs 133.8, P < .0001). The average excess narcotic pills prescribed per patient was 51.7 pills. And 71.9% took fewer than 30 narcotic pills; 90.9% patients took fewer than 50 narcotic pills. Also, 10.7% did not require any narcotics; 9.9% required a refill of narcotics; and 33.1% went home the day of surgery. CONCLUSION: Significantly more narcotics were prescribed than were taken in the postoperative period following THA with an average 51.7 excess narcotic pills per patient. Adjusting prescribing patterns to match patient narcotic usage could reduce the excess narcotic pills following THA.

Cognitive function and quality of life in older adult patients with cochlear implants.

Objective: This study aimed to evaluate the benefits of cochlear implant (CI) on speech perception, quality of life (QoL), and cognitive function in profoundly deafened older adults.Design: Longitudinal and cross-sectional cohort study.Study sample: Participants in this study were CI recipients aged 65 years or older (experimental group), CI recipients aged 50 years or younger (control group 1), and normal-hearing participants aged 65 years or older (control group 2).Results: Speech perception significantly improved in both groups of implanted patients (preoperative vs. 1-year median [IQR] sentence recognition: older patients, 0 (0-20) vs. 90 (70-95), p = 0.001; younger patients, 35 (0-50) vs. 90 (80-100), p = 0.001). There were no significant differences in QoL (Glasgow Benefit Inventory) between younger and older patients (median [IQR] overall benefit score, 42 (31-64) vs. 53 (39-69), p = 0.2). Mini-Mental State Examination scores showed no significant differences between elderly CI recipients and normal-hearing participants (median [IQR], 28 (26-28) vs. 28 (27-29), p = 0.5).Conclusions: Cochlear implantation rehabilitation allows the profoundly deafened older adult to lead a QoL comparable to that of a younger patient. The correlation between hearing restoration and cognitive function preservation in older adults suggest a possible role for CI as a useful resource in limiting age-related cognitive decline.

Endoscopic approach to the round window through posterior tympanotomy for cochlear implantation in children: A study on feasibility.

OBJECTIVE: To demonstrate the feasibility of rigid endoscopy through posterior tympanotomy, which provides both a view of the round window and direction of the scala tympani in children. METHODS: After a standard mini-invasive surgical approach with postauricular access and transmastoid posterior tympanotomy of 2 mm, a 0°, 1.9 mm diameter and 11 cm long endoscope is positioned in proximity of the upper part of the posterior tympanotomy to obtain a panoramic view of the inferior part of the medial wall of the tympanic cavity. Surgical complications and changes in hearing threshold were analyzed. RESULTS: Eight children were submitted to cochlear implantation with endoscopic assistance through posterior tympanotomy. Complete visualization of the round window niche was possible in every ear. No complications related to the procedure were observed. Preoperative threshold was preserved in 9 of 10 ears. CONCLUSIONS: Direct endoscopic view through the posterior tympanotomy allows visualization of the entire round window niche as well as the angle of introduction of the multi-electrode array along the direction of the scala tympani.

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.

Intratympanic steroid delivery by an indwelling catheter in refractory severe sudden sensorineural hearing loss.

OBJECTIVE: Many studies over the last decade showed favorable outcomes with intratympanic (IT) steroid treatment, alone as salvage treatment or in combination with conventional systemic therapy (ST). However, in severe to profound sensorineural hearing loss resistant to ST, the optimal infusion mode, the type and concentration of the solution, the preferable drug, its total amount, and the duration and fractionation of the treatment are still debated. Aim of the study was to investigate the feasibility and the outcomes of a direct and constant IT delivery of dexamethasone (DEX) by means of a new indwelling catheter. METHODS: A prospective case-control study in a tertiary referral university hospital. Ninety-nine subjects treated with ST only and 28 with additional IT DEX have been included in the study. A 4 Fr catheter inserted in a sub-annular fashion with a minimal postero-inferior tympanotomy through and endocanalar approach under local anesthesia. DEX 4mg/ml delivered daily, up to 7 days. Daily bone and air-conducted pure tone and speech audiometry were performed with a follow-up at 1, 3, 6 months after treatment. RESULTS: Twenty-one out of 28 patients (75%) refractory to ST gained on average 24.0dB±20.5dB HL after IT-DEX, compared to 35.4% (average 6.7dB±16.6dB HL) of those receiving only medical ST (p<0.001). No significant side effects were noted. CONCLUSION: In severe to profound sudden deafness refractory to conventional ST, the daily perfusion of 4mg/ml DEX through an intratympanic catheter is an easy, well accepted procedure that enables patients to receive a drug in the middle ear in a repeatable or sustained form, with minimal discomfort and a partial rescue (67.86%) and a speech recognition gain of 39%.

Mechanical comparison of iliosacral reconstruction techniques after sarcoma resection.

BACKGROUND: Reconstruction of iliosacral defects following oncologic resection is a difficult clinical problem associated with a high incidence of failure. Technical approaches to this problem are heterogeneous and evidence supporting specific techniques is sparse. Maximizing construct stability may improve union rates and functional outcomes. The purpose of this study is to compare construct stiffness, load to failure, and mechanism of failure between two methods of iliosacral reconstruction in an ex-vivo model to determine if either is mechanically superior. METHODS: Eight third-generation composite pelves reconstructed with a plate-and-screw technique were tested against seven pelves reconstructed with a minimal spinal instrumentation technique using axial loading in a double-leg stance model. FINDINGS: The pelves from the plate group demonstrated higher stiffness in the direction of applied load (102.9 vs. 66.8N/mm; p=0.010) and endured a significantly larger maximum force (1416 vs. 1059N; p=0.015) than the rod group prior to failure. Subjectively, the rod-reconstructed pelves were noted to be rotationally unconstrained while pivoting around their single point-of fixation in each segment leading to earlier failure. INTERPRETATION: Plate-reconstruction was mechanically superior to spinal instrumentation in the manner performed in this study. More than one point of fixation in each segment should be achieved to minimize the risk of rotational deformation.

Preliminary results of video Head Impulse Testing (vHIT) in children with cochlear implants.

OBJECTIVE: To evaluate the lateral semicircular canal high frequency vestibulo-oculomotor reflex (LSC HF VOR) in children with cochlear implant. METHODS: 16 children (10 females and 6 males, age range = 5-17 years) receiving a unilateral (n = 12) or a bilateral (n = 4) cochlear implant were included and compared to a control group of 20 age-matched normal-hearing (NH) children. Both implanted and NH children received a vestibular function test battery, including a Vestibulo-Ocular Reflex (VOR) gain assessment by means of a video-Head Impulse Test (vHIT), which represented the main outcome measure. In implanted subjects, vHIT was measured on both sides in the "CI-ON" and "CI-OFF" conditions. RESULTS: Overall, no significant LSC HF VOR gain difference was found between CI users and NH peers. In the unilaterally implanted group, the LSC HF VOR gain measured in the "CI-ON" condition was significantly higher than in the "CI-OFF" condition, both in the implanted and in the non-implanted ear. In the bilaterally implanted group there was no such a difference between the two conditions, on either side. CONCLUSION: This is the first study investigating the LSC HF VOR gain in children with unilateral and bilateral CI. The study demonstrates that the LSC HF VOR of bilaterally implanted children is comparable to normal hearing children.