The 28th Brussels Hand/Upper Limb Symposium, with as topic per-operative sonography, should have taken place in Genval in March 2020. It was first delayed, then finally cancelled, because of the Covid19 pandemics. As a substitute, some lectures of the symposium have been published as a written symposium in a special issue of the journal Hand Clinics. As the pandemics is now hopefully over, it is time to meet again - and that the Genval symposium finally takes place.

Interestingly enough, operative sonography has progressed much since 2020. Sonography was until now recently and still at many places used essentially for diagnosis, with the exception of ultrasound-guided biopsies and injections. But now, the physicians, whether surgeons, radiologists, rheumatologists, or physical medicine specialists, dispose of a new tool to guide their operations, sonography. New minimally-invasive sono-guided techniques have emerged. Sonography now goes to the operative room, not only on the side of the anaesthesiologist, but also to assist the surgeon. But also, some percutaneous operations can now also be performed under sonography in the outpatient clinic setup (« office surgery »). Sonography allows excellent visualization of anatomical structures, making surgery under sonography with adapted instruments probably safer than endoscopic surgery, even maybe than open surgery. Of course, all these progresses need to be confirmed by prospective clinical studies.

The new surgical sonography-guided possibilities seem endless, but much remains to be developed. The precise indications are presently poorly defined. Some examples of existing or possible future applications : bone fixation can be performed under sonography instead of under C-arm guidance (metacarpal and scaphoid fractures). Sonography allows good imaging of ligaments (including the scapholunate complex), possibly allowing percutaneous sono-guided repair. In case of joint stiffness, sonography-assisted release can be performed, and sonography allows then also to assess regained joint motion. Sonography allows to precisely localize the pedicle of joint ganglions, allowing safe percutaneous treatment (preserving for example the radial pedicle for palmar wrist ganglions). Sonography allows accurate and safe access to foreign bodies and sometimes percutaneous removal. But the most interesting use of sonography is probably to guide minimally invasive release of trigger finger, carpal tunnel, de Quervain, lateral epicondylitis, lacertus and of other degenerative tendon conditions, and to assist in percutaneous aponeurotomy for Dupuytren and in tenolysis. In peripheral nerve and brachial plexus surgery, sonography allows peroperative assessment of the nerve fascicular structure, which could be helpful in neuroma or in continuity nerve lesion treatment, in conjunction with electrostimulations and operative findigs. Sonography also nicely evaluates nerve dynamics. Of course, sonography has other more classical applications, for guided percutaneous infiltrations, injections and radiofrequency, for acupuncture, for treatment of calcifications, to find a vascular pedicle before harvesting a flap, or to assess the state of flow in an artery after microsurgical repair. Another very interesting potential application is the peroperative assessment of the mechanical properties of the operated biological tissues. Ultrasound can also be used to guide navigation tools. All these principles could in the future be extended to other anatomical locations, in particular to the foot.

The Brussels Hand/Upper Extremity Symposium, following its successful tracks of 25 Genval and two BHS Eu symposia, will be back in Genval on April 5 - 6, 2024 for this first international congress on peroperative sonography in hand/upper extremity surgery. The primary goals of the Brussels/Genval annual upper limb Symposium, gathering together in a first-class resort close to Brussels experts from different fields (the previous Symposia have been attended by orthopaedic, plastic, paediatric and general surgeons, anatomists, physiotherapists, rheumatologists, anaesthesiologists, pain specialists, radiologists, nuclear medicine scientists, immunologists, pathologists, engineers and basic scientists), are to promote the exchange of new ideas, to establish guidelines on a consensual basis, and to foster collaborative investigations among various specialists. Much time will be set aside for the discussions. Please join us in 2024 ! Presentations will be by invited faculty, but a limited number of free papers will be as well accepted.