Post-procedural X-ray Research Articles

Dual Chamber Pacemaker Implant in Coronary Sinus Leading to Several Complications

Permanent pacemaker implantation is a low-risk procedure. However, complications may occur at a rate of around 4–8%. We present a case where initial implantation resulted in complications that could have been avoided by meticulous assessment of lead position in different projections and early post-procedure X-ray that would have delineated other serious complications. We present a case where the right ventricular lead was placed in the coronary sinus, which resulted in the loss of pacing capture with further syncope after the pacemaker implant. This was apparent in the post-procedure electrocardiogram (ECG) with right bundle branch pacing and the lead was repositioned in the right ventricular apex the following day. Furthermore, the patient was discharged home without a chest X-ray (CXR), and she represented a week later with a haemo-pneumothorax and pericardial effusion. A chest drain was placed and was discharged after a slow recovery following several complications that could have been avoidable.

Evaluating emergency department tube thoracostomy: A single-center use of trauma video review to assess efficiency and technique.

Emergency department tube thoracostomy is a common procedure; however, assessing procedural skills is difficult. We sought to describe procedural variability and technical complications of emergency department tube thoracostomy using trauma video review. We hypothesized that factors such as hemodynamic abnormality lead to increased technical difficulty and malpositioning. Using trauma video review, we reviewed all emergency department tube thoracostomy from 2020 to 2022. Patients were stratified into hemodynamically abnormal (systolic blood pressure <90 or heart rate >120) and hemodynamically normal (systolic blood pressure ≥90 or heart rate ≤120). Emergency department tube thoracostomies outside of video-capable rooms, with incomplete visualization, or in patients undergoing cardiopulmonary resuscitation or resuscitative thoracotomy were excluded. The primary outcome was a procedure score modified from the validated tool ranging from 0 to 11 (higher score indicating better performance). Also measured were procedural times to (1) decision to place, (2) pleural entry, and (3) procedure completion. Postprocedure x-ray and chart review were used to determine accuracy. In total, 51 videos met the inclusion criteria. The median age was 34 [interquartile range 24-40] years, body mass index 25.8 [interquartile range 21.8-30.7], predominately male (75%), blunt injury (57%), with Injury Severity Score of 22 [14.5-41]. The median procedure score was 9 [7-10]. Emergency department tube thoracostomies in patients with abnormal hemodynamics had significantly lower procedure scores (8 vs 10, P < .05). Hemodynamically abnormal patients had significantly shorter times from decision to proceed to pleural entry (4.05 vs 8.25 minutes, P < .001), and to completion (6.31 vs 14.23 minutes, P < .001). The most common complication was malpositioning (35.1%), with no significant difference noted when comparing hemodynamically normal and abnormal patients (P= .41). Using trauma video review we identified significant procedural variability in emergency department tube thoracostomy, mainly that hemodynamic abnormality led to lower proficiency scores and increased malpositioning. Efforts are needed to define procedural benchmarks and evaluation in the context of patient outcomes. Using this technology and methodology can help establish procedural norms.

Ultrasound versus intracavitary electrocardiography for intraprocedural tip location during central venous catheterization in infants and children: A prospective clinical study.

Both intracavitary electrocardiography (IC-ECG) and ultrasound (US) have been proven to be safe and accurate for intraprocedural tip location during central venous catheterization, and both are known to be easily applicable and feasible in pediatric patients. Though, no prospective clinical study has directly compared the two methods as regards their applicability, feasibility, and procedural time. This study prospectively enrolled all children requiring a central venous access device in non-emergency situations, during a period of 1 year. All devices were inserted according to a well-defined insertion bundle including both IC-ECG and US-based tip location. The primary endpoint of the study was to compare the two methods in terms of applicability, feasibility and time required. This study included 100 consecutive central venous catheterizations in children of age ranging from 1 month to 18 years. The applicability of IC-ECG based tip location was 98% and its feasibility 100%; the time required for IC-ECG was 1.9 ± 2 min. The applicability of US-based tip location was 96% and its feasibility was 100%; the maneuver required 2.2 ± 3 min. US is an appropriate alternative method for intraprocedural tip location in children. The combined use of US and IC-ECG (both maneuvers being accurate, inexpensive, cost-effective, non-invasive, and equally fast to perform) should be recommended for tip location in pediatric patients, and it will avoid completely the use of fluoroscopy or of post-procedural x-ray.

Hounsfield Units (HU) as a Predictor of Stone Clearance after Percutaneous Nephrolithotomy (PCNL)

Objective: To compare the outcomes of percutaneous nephrolithotomy (PCNL) in patients with renal stones with high (≥700) versus low (&lt;700) HU. Patients and Methods: A total of 200 patients having age 18 to 60 years, with diagnosis of unilateral renal stone disease, having stone size 2 to 4 cm in diameter on non-contrast computed tomography (NCCT) of Urology Unit of Ibn e Sina Hospital and Research Institute Multan were included. The study duration was May-2021 to July-2021. NCCT was done pre-operatively in every patient to measure Hounsfield units (HU). Post-procedural X-ray KUB was done 2 weeks after the surgical procedure to determine the stone clearance in every patient. Results: Mean age was 45.79±11.17 Years. Mean duration of disease of patients included in this study was 8.78±8.59 months. Mean stone size in patients included in this study was 3.11±0.61 cm. On comparison of stone clearance rate between the patients having high-HU versus low-HU, stone clearance was found in 61 (72.6%) patients having low HU value and in 105 (90.5%) patients having high HU value (p-value 0.001). Conclusion: HU-value ≥700 is a significant predictor of success rate of percutaneous nephrolithotomy (PCNL) in patients having renal stone disease. Keywords: Renal Stone Disease, Percutaneous nephrolithotomy, Hounsfield units (HU).

Syringe needle-cap use as novel, static, uni-planar or bi-planar, mini-external fixator for treatment of intra-condylar phalangeal fractures

Background: Comminuted intra-articular phalanx fractures are complicated injuries often treated with external fixation. Syringe needle- cap can be an excellent mini-external fixators because they are radiolucent, readily available, inexpensive, simple, safe and easy to use. Our cases received a novel treatment in the form a syringe needle-cap/mini external fixator that was originally placed in static mode for 3 weeks and then later removed in OPD visit to a dynamic-mode of ROM to allow rehabilitation of the PIPJ/DIPJ. Our cases illustrates the power and utility of this ‘static’ uniplanar or biplanar stable technique to treat intra-condylar phalanx fractures and achieved good functional recovery of finger.Methods: This was a prospective case study covering period from January 2021 to May 2022 at department of plastic surgery, Command Hospital, Chandimandir, Panchkula, Haryana, India. 10 young male patients were presented with intra-articular fractures of phalanx. All patients had undergone pre-operative and post procedure X-rays for evaluation. A static external fixator consisting of a uniplanar or biplanar 2 ml syringe needle-cap and 0.8mm small size (3-4 cm) Kirschner wires as an optimal fixator across the fractured joint. K-wires were removed in OPD visit after 3 weeks to dynamize the ROM of affected joint of finger post-operatively.Results: 10 male patients were studied with average age of 28 years. 06 of them are intra-condylar fractures at PIP joints and rest are intra-articular fractures. After 3 weeks, we removed this fixator device and started controlled physiotherapy. End results notified in our study were achievement of good functional recovery of finger ROM at 3 months follow up.Conclusions: Syringe needle-cap use as mini-external fixation should be considered as a novel tool in the treatment of comminuted intra-articular phalangeal fracture.

Placement of LC-II and trans-sacral screws using a robotic arm in a simulated bone model in the supine position \u2013 a feasibility study

PurposeThe use of a robotic arm has been well-described in the literature for the placement of pedicle screws in spine surgery as well as implants for sacroiliac joint fusion. There are no reports describing the use of a robotic arm to place screws in osseous fixation pathways (OFPs) employed in the treatment of pelvic ring and acetabular fractures outside of a single center in China. Using a Sawbones model, the authors describe a technique for using a robotic arm widely available in Europe and the Americas for placement of 6.5 mm cannulated screws into two OFPs commonly used in the treatment of pelvic and acetabular fractures.MethodsUsing the Mazor X Stealth Edition (MSXE) robot from Medtronic, the authors were able to place a pin into the pelvis onto which the robot was docked. The authors were then able to designate the area of interest using navigated instruments, and in combination with the MSXE “scan and plan” marker, obtain cross-sectional imaging using the O-Arm and successfully register the MSXE robot. We then used the provided software to plan trajectories for the lateral compression type 2 (LC-II) screw pathway as well as a pathway for a trans-ilio-trans-sacral screw. We describe in detail the steps for setup, planning and placement of 6.5 mm cannulated screws using the MSXE robotic arm into these two OFPs.ResultsVisual inspection and plain x-rays demonstrated successful placement of the screws into the two planned OFPs. No breach of cortical bone was seen on either visual inspection of the model or demonstrated on post-procedure x-rays.ConclusionIt is possible to use the Mazor X Stealth Edition robot to place screws into the LC-II and trans-ilio-transsacral screw pathways in a Sawbones model. This is only a feasibility study, and should in no way be taken to suggest that clinical application of this technique should be attempted.

Lumbar Radiofrequency Ablation Cannula and Probe Complications: Source for Potential Foreign Body

BACKGROUND: Radiofrequency ablation is a common approach for treating axial low back pain stemming from facet arthropathy. Many well-published complications have been addressed in the literature. This case demonstrates a hardware malfunction and underscores the importance of vigilance toward protocols to maintain radiofrequency probes during sterilization and reuse. CASE REPORT: In our case, the patient underwent a successful bilateral 2-level neurotomy. At the completion of the procedure, we removed all instruments and found that the probe was no longer attached to the connector. Multiple postprocedure x-rays were negative for a foreign body; the probe was later found in the cannula intact. This case report illustrates a rare potential complication for foreign body retention in an outpatient setting. CONCLUSION: Appropriate maintenance and handling of reusable probes during sterilization and use must be exercised. Alternatives include the use of disposable probes and connector cables. KEY WORDS: Radiofrequency ablation, foreign body, probe

Inadvertent arterial puncture involving the subclavian artery and the aorta during central venous catheterization: a case report

BackgroundThis case report describes a subclavian vein cannulation that inadvertently led to an arterial puncture with the catheter tip radiologically seen at the level of the aorta. This case emphasizes the importance of postprocedural imaging and the disadvantages of not using ultrasound guidance in central venous catheterization.Case presentationA 24-year-old Caucasian man with diabetes mellitus type 1 presented himself to the emergency department due to abdominal pain accompanied by nausea and vomiting. The patient’s vital signs revealed blood pressure of 84/53 mmHg, heart rate of 103 beats per minute, respiratory rate of 18 breaths per minute, and temperature of 98.2 °F (36.7 °C). On physical examination, he was found to have dry oral mucosa with poor skin turgor, with diagnostics showing that he was in diabetic ketoacidosis after running out of insulin for 2 days. The patient was transferred to the intensive care unit to receive a higher level of care. Unfortunately, due to difficulty of peripheral line placement, only a gauge-22 cannula was secured at the left dorsum of the hand. Efforts to replace the current peripheral line were unsuccessful, and a decision to perform a central vein cannulation via the internal jugular vein was made. This was futile as well due to volume depletion, prompting a subsequent right subclavian vein route attempt. The procedure inadvertently punctured the arterial circulation, leading to the catheter tip being visible at the level of the aorta on postprocedure X-ray. The subclavian line was immediately removed with no adverse consequences for the patient. A right femoral line was successfully placed, and continuous management of the diabetic ketoacidosis ensued until normalization of the high anion gap was achieved.ConclusionUtilization of real-time ultrasound guidance via the subclavian approach could have allowed for direct visualization of needle insertion to the anatomical structures, guidewire location, and directionality, all of which can lead to decreased complications and improved cannulation success compared with the landmark technique. A leftward direction of the catheter seen on postprocedural X-rays should raise high suspicion of inadvertent catheter placement and immediate correction. This complication should have been prevented if ultrasound guidance had been used.

Comparison of catheterization of internal jugular vein by ultrasound guided versus landmark approach IN I.C.U. patients

Comparison of catheterization of internal jugular vein by ultrasound guided versus landmark approach IN I.C.U. patients - IJCA- Print ISSN No: - 2394-4781 Online ISSN No:- 2394-4994 Article DOI No:- 10.18231/2394-4994.2018.0082, Indian Journal of Clinical Anaesthesia-Indian J Clin Anaesth

Ultrasound-guided L5 dorsal ramus block: validation of a novel technique

BackgroundAlthough the value of ultrasound-guided (USG) lumbar medial branch blocks (MBB) has previously been examined in several clinical trials, blocking the L5 dorsal ramus (DR) remains a technical challenge and...

Comparison of JSS Formula with Modified Shukla’s Formula for Insertion of Umbilical Venous Catheter: A Randomized Controlled Study

To compare the rate of optimal position of UVC between modified Shukla's formula and JSS formula. Babies requiring umbilical vein catheterization were randomized to either Shukla or JSS formula group. Post-procedure X-ray was taken to check the tip position. Tip of the UVC just above the diaphragm (T9 - T10) was considered optimal. Success rate in achieving optimal position between the two groups were compared. Out of 104 babies recruited, 50 were randomized for Shukla's formula and 54 for JSS formula. Catheter tips were in acceptable positions in 39.6% of Shukla group as compared to 56% in JSS group (P=0.02). The JSS Formula resulted in more optimal placement of UVC than the modified Shukla formula.

Simulation-Based Education Enhances Patient Safety Behaviors During Central Venous Catheter Placement.

We describe the effect of simulation-based education on residents' adherence to protocols for and performance of central venous access. Internal medicine and emergency medicine residents underwent a central venous access course that included a lecture, video presentation, readings, and simulation demonstrations presented by faculty. Baseline data were collected before the course was initiated. After a skills session where they rehearsed their ultrasound-guided central venous access skills, residents were evaluated using a procedural checklist and written knowledge exam. Residents also completed questionnaires regarding confidence in performing ultrasound-guided central venous access and opinions about the training course. Residents demonstrated significant improvement on the written knowledge exam (P < 0.0001) and Standard Protocol Checklist (P < 0.0001) after the training course. Training improved a number of patient safety elements, including adherence to sterile technique, transparent dressing, discarding sharps, and ordering postprocedure x-rays. However, a number of residents failed to wash their hands, prepare with chlorhexidine, drape the patient using a sterile technique, anesthetize the site, and perform a preprocedure time-out. Significant improvement in procedural skills was also noted for reduction in skin-to-vein time (P < 0.003) as well as a reduction in number of residents who punctured the carotid artery (P < 0.02). Simulation-based education significantly improved residents' knowledge and procedural skills along with their confidence. Adherence to the protocol also improved. This study illustrates that simulation-based education can improve patient safety through training and protocols.

Recurrence of fatal venous air embolism.

Venous air embolism (VAE) often occurs in the operating theatre. Squeals have not been reported much in most recovering patients. Our patient recovered from a venous air embolism during surgery but experienced cardiac arrest in the intensive care unit the next day, and died. A review of the chest X-ray revealed pulmonary edema and intracardiac air. A 42-year-old male patient was admitted for surgery on a right occipital brain meningioma. The patient had no specific medical history. The right subclavian vein was cannulated dur ing the preoperative period. In the operating theatre, non-invasive blood pressure, electrocardiograph, pulse oximeter (SpO2), end-tidal carbon dioxide (ETCO2) and central venous pressure (CVP) monitoring were initiated. Anesthesia was maintained with oxygen, air, target-controlled infusion of remifentanil and propofol, and rocuronium with controlled ventilation. The left dorsalis pedis artery was cannulated for continuous arterial blood pressure monitoring (ABP). The surgery was performed in the semi-sitting position. One hour after beginning the surgery, an abrupt CVP elevation from 8 to 18 cmH2O was detected. ETCO2 decreased from 20 to 14 mmHg, and systolic ABP decreased from 110 to 92 mmHg. After injecting 5 mg ephedrine, blood pressure increased but decreased again. Although we suspected a pneumothorax during cannulation of the central line, both lung sounds were symmetrical and a post-procedural X-ray did not reveal a pneumothorax. Sinuses had not been cut yet, but under strong suspicion of a VAE, BP decreased, heart rate (HR) slowed, and ventricular premature complexes occurred. Surgeon sprayed water over the operative field and wrapped the wound with wet surgical pads. The surgery was stopped and the patient was repositioned in the head down position. Aspiration of blood through the central line showed air bubbles. The vital signs stabilized after 1,000 ml of mixed blood and air were aspirated. The cardiologist confirmed that the right heart was enlarged and deviated to the left side on a trans-thoracic echocardiograph (TTE). However, no intracardiac air was detected. When the surgery was being delayed and the surgeon sutured the wound, vital signs became unstable again. We aspirated air from the central line again, and vital signs stabilized. After wound closure, a trans-esophageal echocardiograph (TEE) revealed no intracardiac air. Intracardiac shunts such as foramen ovale were also not detected in TEE. The patient was moved to the ICU without extubation. In the ICU, BP was 140/70 mmHg, HR, 88 beats/min; CVP, 3 cmH2O; and SpO2, 100%. The ventilator was connected with a tidal volume of 450 ml, respiratory rate of 16 breaths/min, fraction of inspiratory oxygen of 1.0, a positive end-expiratory pressure (PEEP) of 5 cmH2O. After a chest X-ray revealed pulmonary edema, the surgeon injected furosemide 20 mg. The Glasgow coma scale score recovered to 9 and after 1 and half hour the patient removed the endotracheal tube accidently. A rebreathing mask with 10 L/min O2 was used, and SpO2 90% was adjusted to 90%. After 30 min, SpO2 decreased to 85% so the patient was reintubated and a diuretic infusion was started. Vital signs were; BP, 140/80 mmHg; HR, 150 bpm; PEEP increased to 7 cmH2O, and fluid was restricted. BP dropped to 70/50 mmHg and a norepinephrine infusion was started 2 hr later. A chest anteroposterior view and brain computed tomography (CT) scan were conducted. The brain CT revealed no other abnormality. Although we increased the norepinephrine dosage, the patient

The Intracavitary ECG Method for Positioning the Tip of Central Venous Catheters: Results of an Italian Multicenter Study

The aim of this multicenter study was to assess the feasibility, safety, and accuracy of the intracavitary ECG method for real-time positioning of the tip of different types of central venous catheters. A total of 1444 catheter insertions in adult patients were studied in eight Italian centers (539 ports, 245 PICCs, 325 tunneled CVCs, 335 non-tunneled CVCs). Patients with no visible P wave at the standard baseline ECG were excluded. Depending on the type of catheter and its purpose, the target was to position the tip either (a) at the cavo-atrial junction, or (b) in the lower third of the superior vena cava, or (c) in the upper part of the atrium. The final position was verified by a post-procedural chest x-ray. The method was feasible in 99.3% of all cases. There were no complications potentially related to the method itself. At the final x-ray control, 83% of all tips were positioned exactly at the target; 12.4% were positioned within 1-2 cm from the target, but still in a correct central position; only 3.8% were malpositioned. The mismatch between intra-procedural ECG method and post-procedural x-ray was significantly lower when the x-ray was taken in supine position. Our multicenter study confirms that the intracavitary ECG method for real time verification of tip position is accurate, safe, feasible in all adult patients and applicable to any type of short-term or long-term central venous access device.

Trapézectomie partielle arthroscopique : étude radioanatomique de 14 cas

Objectives The aim of the study was to assess the accessibility of the trapezium surface to arthroscopic resection related to the degenerative stage, to define the surgical approach and to determine the efficacy of the X-rays for evaluating the amount of resected bone. Methods Fourteen trapezectomies were performed on seven cadaveric specimens using an arthroscopic procedure. Pre- and post-procedure X-rays were used to assess the initial trapeziometacarpal osteoarthritis and the resection performed. Each subject was randomized for using two posterior portals or two posterior portals and one anterior portal. At the end of the procedure, a dissection was performed for evaluating the quality of resection and the anatomical relationship of each surgical approach. Results The stages of preprocedure osteoarthritis were comparable between the two sides of the same cadaveric specimen. On post-procedure X-rays, the resection appeared complete in only six out of 14 wrists. During dissection, no injury to neurovascular structures was observed, and the resection was visible macroscopically in 11/14 wrists. Three resections were incomplete, i.e., less than 20 % of total trapezial surface: two of them were seen in the most osteoarthritic cases of the study. Conclusions The arthroscopic approach presents an opportunity to access the entire trapezial surface, even if a high stage of osteoarthritis appears to be a risk for incomplete resection. The addition of a systematic anterior approach to the traditional dorsal approach does not increase the accessibility. Although radiography is not the most appropriate tool to assess the resected surface, it does help to locate the defects of resection and can guide the surgical procedure in situations where there is a risk of incomplete resection.

Incidence and Characteristics of Potential and Actual Retained Foreign Object Events in Surgical Patients

Incidence of retained foreign objects (RFOs) after operations is unknown, as many can go unrecognized for years. We reviewed the incidence and characteristics of surgical RFO events at a tertiary care institution during 4 years. All RFO events, near misses and actual, reported on an adverse event line during 2003 to 2006 were reviewed. During 2003 to 2006, there were 191,168 operations performed, with 68 reported events resulting in a potential RFO defect rate of 0.356/1,000 patients. After review, 34 patients had no RFOs (near misses) and 34 were actual RFOs, resulting in a true RFO defect rate of 0.178/1,000 operations or approximately 1:5,500 operations. In the near-miss patient, needles were miscounted 76% of the time. In the 34 actual RFO patients, items retained were 23 sponges (68%), 7 miscellaneous other items (20%), 3 needles (9%), and 1 instrument (3%). The 34 actual RFOs occurred in incidents where the count had been reported as correct in 21 patients (62%). In 18 patients where an RFO was eventually discovered, intraoperative imaging detected only 12 objects (67%). In operations involving a body cavity, our practice is to obtain a high-resolution x-ray survey film, in a dedicated x-ray suite, before entering the recovery room. Twenty RFOs were identified from survey films and all occurred in patients with correct counts. No RFOs occurred during emergency or high blood-loss procedures and none resulted in demonstrable clinical harm. Two patients left the hospital with an RFO. Twenty-two patients (64.8%) underwent reoperation, with 1 object not removed, 6 (17.6%) retrieved without operation, and 6 (17.6%) where the clinical decision was not to remove. RFOs at an institution that routinely performs postprocedure x-rays indicate that RFOs can occur more frequently than expected from the literature. The majority occur in patients with correct counts. Relying on counting as the primary mechanism to avoid RFOs is unreliable, and investigating new technologies designed to achieve reliable counts is warranted.

Image‐guided and ‐monitored renal artery stenting using only MRI

To demonstrate the ability of a unique interventional MR system to be used safely and effectively as the only imaging modality for all phases of MR-guided stent-supported angioplasty. An experimental disease model of renal stenosis was created in six pigs. An interventional MR system, which employed previously reported tools for real-time catheter tracking with automated scan-plane positioning, adaptive image parameters, and radial true-FISP imaging with steady-state precession (True-FISP) imaging coupled with a high-speed reconstruction technique, was then used to guide all phases of the intervention, including: guidewire and catheter insertion, stent deployment, and confirmation of therapeutic success. Pre- and postprocedural X-ray imaging was used as a gold standard to validate the experimental results. All of the stent-supported angioplasty interventions were a technical success and were performed without complications. The average postoperative residual stenosis was 14.9%. The image guidance enabled the stents to be deployed with an accuracy of 0.98 +/- 0.69 mm. Additionally, using this interventional MRI system to guide renal artery stenting significantly reduces the procedure time, as compared to using X-ray fluoroscopy. This study has clearly demonstrated the first successful treatment of renal artery stenting in an experimental animal model solely under MRI guidance and monitoring.

Un nouvel implant pour les fractures de l’humérus proximal : la plaque à corbeille: Étude expérimentale

Purpose of the study We conducted a comparative study of three ostheosynthesis systems for proximal humeral fractures. The conclusions led to the elaboration of a rigid extramedullary osteosynthesis implant. This novel implant allows specific fixation of the tuberosities via six adjustable and removable hooks organized like a basket. There are two versions, with and without a central cephalic locking screw. We report two static biomechanical studies conducted to analyze this material. Material and methods The two studies were performed on fresh frozen cadaver specimens with known bone density and with an experimental model of a four-fragment fracture of the proximal humerus. The first tests were designed to measure axial pressure reproducing the physiological movement applying the most stress on the head of the humerus. This allowed a global analysis of the mechanical behavior of the implant and an assessment of the contribution of the central cephalic locking screw. The second series of tests were traction tests used to analyze the behavior of the tuberosities fixed with the hooks. We assess the assemblies by measuring the mechanical resistance: rigidity of the fixation was recorded in mm/100N. Pre- and post-procedure x-rays and photographs were obtained to allow a subjective assessment of fragment displacement. Results The first series of tests demonstrated that the implant, with the central cephalic locking screw, presented good overall mechanical properties. The notion of better stability of the tuberosities obtained with the hooks, as seen during the first tests, was reinforced by the data from the second tests, although no statistically significant difference was demonstrated. We also noted that there was no statistically significant correlation between bone density and the slopes of the force-resistance curves. Discussion This prototype implant has an overall mechanical resistance equivalent to the reference implant, with at least equivalent performance. Proof of the usefulness of the central locking screw was not established, even though improved tolerance to loading by better force distribution seemed apparent. The contribution of the hook basket was not demonstrated. Data from the observations do however suggest the expectations of the implant will be fulfilled. Tests conducted on a larger scale would probably demonstrate a difference. It is clear that the small number of implants used here limited the study. Comparison with data in the literature show that this new prototype is adapted to the mechanics of the proximal humerus. Resistant to physiological stress, the implant allows pendular movement and passive physical therapy during the early post-operative period.