Current state of the art and future directions for implantable sensors in medical technology: Clinical needs and engineering challenges.

Implantable sensors have revolutionized the way we monitor biophysical and biochemical parameters by enabling real-time closed-loop intervention or therapy. These technologies align with the new era of healthcare known as healthcare 5.0, which encompasses smart disease control and detection, virtual care, intelligent health management, smart monitoring, and decision-making. This review explores the diverse biomedical applications of implantable temperature, mechanical, electrophysiological, optical, and electrochemical sensors. We delve into the engineering principles that serve as the foundation for their development. We also address the challenges faced by researchers and designers in bridging the gap between implantable sensor research and their clinical adoption by emphasizing the importance of careful consideration of clinical requirements and engineering challenges. We highlight the need for future research to explore issues such as long-term performance, biocompatibility, and power sources, as well as the potential for implantable sensors to transform healthcare across multiple disciplines. It is evident that implantable sensors have immense potential in the field of medical technology. However, the gap between research and clinical adoption remains wide, and there are still major obstacles to overcome before they can become a widely adopted part of medical practice.

Bilateral Ulnar Nerve Injury in the Wrist: Comparison of First Webspace Muscle Reconstruction by Opponens Nerve Transfer in the Right Hand Versus Direct Ulnar Nerve Repair in the Left Hand.

We report a case of a bilateral glass injury to the wrist with transection of flexor tendons and the ulnar nerve and artery in a 60-year-old male patient. Two days after his accident, we repaired all divided structures, and on the right hand, we added the transfer of the opponens motor branch to the deep terminal division of the ulnar nerve aimed at first dorsal interosseous and adductor pollicis muscle reinnervation. After surgery, the patient was followed over 24 months. Postoperative dynamometry of the hand, which included grasping, key-pinch, subterminal-key-pinch, pinch-to-zoom, and first dorsal interosseous muscle strength, indicated recovery only in the nerve transfer side.

Acute Compartment Syndrome of the Upper Extremity: Clinical Outcomes Following Surgical Treatment. A Retrospective Cohort Study.

BACKGROUND: Acute extremity compartment syndrome is a surgical emergency for which timely diagnosis is essential. OBJECTIVES: To assess whether the time from the initial insult to the fasciotomy of compartment syndrome of the upper extremity affects outcomes and to examine the differences between compartment syndrome secondary to fractures and that resulting from a non-fracture etiology with regard to the time from insult to fasciotomy and the long-term patient outcomes. METHODS: Patients presented with documented fasciotomy treatment following acute upper extremity compartment syndrome and a minimum of 6 months follow-up. Patient information included demographics, cause of compartment syndrome, method of diagnosis, and outcome on follow-up. RESULTS: Our study was comprised of 25 patients. Fasciotomies were performed for compartment syndrome caused by fracture in 11 patients (44%), and due to insults other than fractures in 14 patients (56%). The average time to fasciotomy in patients without a fracture was 10.21 hours and 16.55 hours with a fracture. Fasciotomy performed more than 24 hours from the initial insult was not found to significantly affect long-term sequelae compared to fasciotomy performed earlier than 24 hours from the initial insult. The non-fracture group had more long-term sequelae than the fracture group (13/15 patients and 5/11 patients, respectively). CONCLUSIONS: Most injuries treated for fasciotomy of compartment syndrome were non-fracture related, with more complications found in patients with non-fracture related injuries. Time interval from insult to fasciotomy did not affect outcome and was longer in the fracture group, suggesting longer monitoring in this group and supporting fasciotomy even with late presentation.

Restoring Tactile Sensation Using a Triboelectric Nanogenerator.

Loss of tactile sensation is a common occurrence in patients with traumatic peripheral nerve injury or soft tissue loss, but as yet, solutions for restoring such sensation are limited. Implanted neuro-prosthetics are a promising direction for tactile sensory restoration, but available technologies have substantial shortcomings, including complexity of use and of production and the need for an external power supply. In this work, we propose, fabricate, and demonstrate the use of a triboelectric nanogenerator (TENG) as a relatively simple, self-powered, biocompatible, sensitive, and flexible device for restoring tactile sensation. This integrated tactile TENG (TENG-IT) device is implanted under the skin and translates tactile pressure into electrical potential, which it relays via cuff electrodes to healthy sensory nerves, thereby stimulating them, to mimic tactile sensation. We show that the device elicits electrical activity in sensory neurons in vitro, and that the extent of this activity is dependent on the level of tactile pressure applied to the device. We subsequently demonstrate the TENG-IT in vivo, showing that it provides tactile sensation capabilities (as measured by a von Frey test) to rats in which sensation in the hindfoot was blocked through transection of the distal tibial nerve. These findings point to the substantial potential of self-powered TENG-based implanted devices as a means of restoring tactile sensation.

Effectiveness of Distal Nerve Transfers for Claw Correction With Proximal Ulnar Nerve Lesions.

PURPOSE: To evaluate claw deformity correction following anterior interosseous nerve (AIN) end-to-end transfer to the deep motor branch of the ulnar nerve (DMBUN) in high ulnar nerve injuries. METHODS: Eleven patients were retrospectively evaluated for metacarpophalangeal joint hyperextension and proximal interphalangeal joint extension lag in the fourth and fifth digits following ulnar nerve injury adjacent or proximal to the elbow, who underwent AIN end-to-end transfer to the DMBUN. RESULTS: Patients underwent surgery an average of 5 months following injury (range, 2-9 months) and were followed for an average of 19 months after surgery (range, 12-30 months). At the last follow-up, clawing was observed in all patients, with proximal interphalangeal joint extension lag averaging 46.8° (SD, ±20°) in the fourth digit and 57.7° (SD, ±12°) in the little finger. CONCLUSIONS: None of our patients experienced claw correction after AIN end-to-end transfer to the DMBUN. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The Use of Medicinal Leeches for the Treatment of Venous Congestion in Replanted or Revascularized Digits.

PURPOSE: A noteworthy cause of failure in digital replantation is venous insufficiency. External bloodletting with medicinal leeches is a common treatment for venous insufficiency after distal digital replantations. The objective of this study was to evaluate the salvage rate of digits replanted proximal to the distal interphalangeal (DIP) joint that were treated with medicinal leeches for venous congestion. METHODS: We retrospectively reviewed the charts of patients with complete or incomplete digit amputation admitted between January, 2008 and April, 2014. We included all patients with venous congestion in one or more digits replanted or revascularized at the middle or proximal phalangeal level, who were treated with medicinal leeches. Treatment initiation and duration were based on clinical judgment. Demographic, therapy, and surgical data were collected. RESULTS: Of 145 patients with 205 digits that were replanted or revascularized, 25 digits were treated with medicinal leeches for venous congestion. Venous congestion was diagnosed later than 48 hours after operation in 24 of the 25 digits. Of the 25 digits, 11 survived (44.4%) (8 of 22 replanted digits and all 3 revascularized digits). No complications were recorded except for substantial blood loss requiring transfusion in one patient. CONCLUSIONS: External bloodletting with medical leeches might be less effective with late treatment or with a higher volume of congested tissue, as is characteristic of proximal finger replantation. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

[BISPHOSPHONATES AS A PREVENTATIVE TREATMENT FOR OSTEOPOROTIC HIP FRACTURES: A MIXED BLESSING].

BACKGROUND: The widespread use of bisphosphonates for treating osteoporosis in the last two decades has raised concern about the complication of atypical hip fractures secondary to bisphosphonate treatment. These fractures may be the result of a minor trauma to the hip or without any trauma at all. It may be heralded by prodromal groin or hip pain. Prolonged bisphosphonate treatment and atypical fractures may exist, but the nature and the extent of this linkage are still unknown. Currently, there is a lack of adequate evidence-based methods or a consensus about the treatment of this unique phenomenon. METHODS: We retrospectively examined the records of all subtrochanteric hip fracture cases admitted to our department in the years 2010-2014. During that period, we treated a total of 1315 patients:726 patients with pertrochanteric fractures, 514 patients with subcapital fractures and 75 patients with distal subtrochanteric fractures. Among those, 16 patients (1.2%) qualified as atypical hip fractures. The location of the fracture, period of bisphosphonates use, fixation type, complications and recovery were recorded. RESULTS: The average age of the patients in our study was 76.9 years. All patients were treated with bisphosphonates and over 80% of the patients were treated specifically with Alendronate prior to the fracture. Mean treatment time was 7.8 years. Most of the fractures (75%) were subtrochanteric, and the others were at the femur midshaft. All patients received surgical fixation and all accomplished union of the fractures. CONCLUSIONS: It seems reasonable to assume a causative relationship between a long term use of bisphosphonates and the occurrence of atypical hip fractures. It is a relatively rare complication; nevertheless, it should be kept in mind during a long term use of bisphosphonates. According to our department's clinical experience we found no delay in bone union with these atypical hip fractures. It seems reasonable to prophylactically fixate atypical stress fractures before they become a full fracture.

Atypical fractures of the femur related to prolonged treatment with bisphosphonates for osteoporosis.

BACKGROUND: Bisphosphonates reduce the overall risk of fractures among patients with osteoporosis, and this beneficial effect is long-lasting. However, since bisphosphonates inhibit bone remodeling, they may enhance the formation and propagation of micro-cracks over time and patients may therefore be prone to atypical fatigue fractures, mainly in the subtrochanteric region and femoral shaft. OBJECTIVES: To present two cases of subtrochanteric fractures related to bisphosphonate treatment, and review the current literature. CONCLUSIONS: Despite the overall beneficial effect of bisphosphonates, further research is required to prevent this significant complication.

Guiding femoral rotational growth in an animal model.

BACKGROUND: Guided growth is most commonly utilized about the knee and ankle for the correction of coronal-plane deformities by the use of plates positioned perpendicular to the physis. Sagittal-plane deformity correction has been described as well. The purpose of our study was to examine the ability to affect axial-rotational growth. Our hypothesis was that placement of plates in an oblique orientation relative to the physis can induce rotational growth deformity. METHODS: Our hypothesis was tested with use of a mathematical model and a bone model and subsequently in a rabbit model. Thirteen six-week-old rabbits underwent a rotational guided growth procedure involving the distal aspect of the right femur, with a sham procedure performed on the left side. Two plates were positioned in an oblique orientation relative to the physis, medially and laterally, to guide either internal or external rotational growth. After the rabbits were killed six weeks after the surgery, the femoral rotational profile was assessed by computed tomography scans of the dissected femora and the growth plates were examined histologically. RESULTS: A significant effect on the rotational profile was found in the treated femora. When the plates were positioned to guide external rotation, the rotational profile was significantly greater in the treated femora (29.0° compared with 11.3° in the sham femora; p = 0.008). There was a positive linear correlation between the right-left difference in rotational profile and the change in inter-plate angle (R2 = 0.72, p = 0.001). Every 1° of inter-plate angle change induced 0.367° of rotational profile difference (p = 0.001). Histologically, a swirling effect of the physeal cell columns was seen in the treated femora. CONCLUSIONS: Guided growth using plates was demonstrated to alter axial-rotational growth in a predictable fashion in a rabbit model. CLINICAL RELEVANCE: Guided growth using plates may be effective for correction of rotational and multiplanar deformities.

Reversed assembly of total hip arthroplasty components: a surgical tip to facilitate implant reduction during minimally invasive surgery.

Total hip arthroplasty (THA) using minimally invasive surgery (MIS) can result in soft tissue damage during the trial reduction and actual implantation. We present a surgical technique that reduces soft tissue trauma and facilitates implant reduction while protecting the prosthetic head from scratching during MIS THA. Primary THA using MIS was performed in 16 hips through a transgluteul direct lateral approach. Average follow-up was 54 months (range 52-58 months). At latest follow-up there was no evidence for component dissociation or loosening in any of the patients. Reverse assembly of THA components is a viable option, which may facilitate MIS THA and decrease soft tissue trauma.