Hourglass-like constriction of the anterior interosseous nerve in the left forearm:A case report

BACKGROUND Hourglass-like constriction neuropathy is a rare neurological disorder.The main clinical manifestation is peripheral nerve injury with no apparent cause,and the pathomorphological change is an unexplained narrowing of the diseased nerve.The diagnosis and treatment of the disease are challenging and there is no accepted diagnostic or therapeutic approach.CASE SUMMARY This report describes a rare hourglass constriction of the anterior interosseous nerve in the left forearm in a 47-year-old healthy male who was treated surgically and gradually recovered function over a 6-mo follow-up period.CONCLUSION Hourglass-like constriction neuropathy is a rare disorder.With the development of medical technology,more examinations are now available for diagnosis.This case aims to highlight the rare manifestations of Hourglass-like constriction neuropathy and provides a reference for enriching the clinical diagnosis and treatment experience.

Treatment of posterior interosseous nerve entrapment syndrome with ultrasound-guided hydrodissection:A case report

BACKGROUND Posterior interosseous nerve(PIN)entrapment syndrome is one of the causes of weakness and pain of the arm muscles,which is prone to missed diagnosis and misdiagnosis in clinic practice.This paper reports a case of PIN entrapment syndrome,with PIN injury indicated by electrophysiology.Musculoskeletal ultrasound was applied to identify that the entrapment point was located at the inlet of the Frohse arch and the outlet of the supinator muscle.Treatment with ultrasound-guided nerve hydrodissection was performed on the entrapment point,which significantly improved the symptoms.Ultrasound-guided nerve hydrodissection is an effective therapeutic method for PIN entrapment syndrome.CASE SUMMARY A male patient,35 years old,worked as an automobile mechanic.He felt slightly weak extension activity of his right fingers 2 years ago but sought no treatment.Later,the symptoms gradually became aggravated and led to finger drop,particularly severe in the right middle finger,accompanied by supination weakness of the right forearm.Neural electrophysiological examination showed that the patient had partial PIN injury of the right radius.Musculoskeletal ultrasound examination indicated PIN entrapment at the inlet of the Frohse arch and the outlet of the supinator muscle.Therefore,PIN entrapment syndrome was diagnosed.After treatment with ultrasound-guided nerve hydrodissection around the entrapment point,the dorsiflexion weakness of the right hand was significantly improved compared with before treatment.CONCLUSION Ultrasound-guided hydrodissection is efficacious for PIN entrapment syndrome,with high clinical value and great application prospects.

Posterior interosseous nerve localization within the proximal forearm-a patient normalized parameter

AIM To provide a "patient-normalized" parameter in the proximal forearm. METHODS Sixty-three cadaveric upper extremities from thirty-five cadavers were studied. A muscle splitting approach was utilized to locate the posterior interosseous nerve(PIN) at the point where it emerges from beneath the supinator. The supinator was carefully incised to expose the midpoint length of the nerve as it passes into the forearm while preserving the associated fascial connections, thereby preserving the relationship of the nerve with the muscle. We measured the transepicondylar distance(TED), PIN distance in the forearm's neutral rotation position, pronation position, supination position, and the nerve width. Two individuals performed measurements using a digital caliper with inter-observer and intraobserver blinding. The results were analyzed with the Wilcoxon-Mann-Whitney test for paired samples. RESULTS In pronation, the PIN was within two confidence intervals of 1.0 TED in 95% of cases(range 0.7-1.3 TED); in neutral, within two confidence intervals of 0.84 TED in 95% of cases(range 0.5-1.1 TED); in supination,within two confidence intervals of 0.72 TED in 95% of cases(range 0.5-0.9 TED). The mean PIN distance from the lateral epicondyle was 100% of TED in a pronated forearm, 84% in neutral, and 72% in supination. Predictive accuracy was highest in supination; in all cases the majority of specimens(90.47%-95.23%) are within 2 cm of the forearm position-specific percentage of TED. When comparing right to left sides for TEDs with the signed Wilcoxon-Mann-Whitney test for paired samples as well as a significance test(with normal distribution), the P-value was 0.0357(significance-0.05) indicating a significant difference between the two sides.CONCLUSION This "patient normalized" parameter localizes the PIN crossing a line drawn between the lateral epicondyle and the radial styloid. Accurate PIN localization will aid in diagnosis, injections, and surgical approaches.

Potential Compressive Sites of the Anterior Interosseous Nerve in the Proximal Forearm: An Anatomic Study

Background: The etiology and treatment of spontaneous paralysis variants of anterior interosseous nerve (AIN) syndrome remains controversial. Variation and multiple sites of potential compression complicate the successful performance of neurolysis. This anatomic study of the AIN and sites of potential compression in the proximal forearm facilitates critical steps involved in neurolytic procedures and management. Methods: Upper extremities of twelve cadavers were examined to evaluate potential sites of AIN compression in the proximal forearm. Potential sites of musculoaponeurotic compression were evaluated, including: lacertus fibrosus;inferior fibrous arch of the humeral head of the pronator teres (PT) muscle;inferior fibrous arch of the ulnar head of the PT muscle;fibrous arch in the flexor digitorum superficialis (FDS) muscle;Gantzer’s muscle;and vascular structures near the AIN and median nerve. Results: The AIN arose at a mean distance of 54.5 mm distal to the elbow from the posterior (n = 9) or ulnar side (n = 3) of the median nerve. Relative positions of AIN branches were variable. A fibrous arch was found between the lacertus fibrosus and the PT in two cases. Nine cadavers had two fibrous arches in the PT and FDS, and three cadavers had one arch. An accessory head in the FDS was found to be a risk of AIN compression. Gantzer’s muscle was present in six cases, crossing the AIN superficially. Two potentially compressive vascular arches were identified. Conclusions: Our observations confirm that multiple musculoaponeurotic and/or vascular structures can contribute to AIN compression in the proximal forearm. Understanding the complex anatomic relationships of this nerve is crucial to improving outcomes of neurolysis in cases of non-regressive AIN paralysis.

Transfer of the extensor indicis proprius branch of posterior interosseous nerve to reconstruct ulnar nerve and median nerve injured proximally:an anatomical study

Proximal or middle lesions of the ulnar or median nerves are responsible for extensive loss of hand motor function.This occurs even when the most meticulous microsurgical techniques or nerve grafts are used.Previous studies had proposed that nerve transfer was more effective than nerve grafting for nerve repair.Our hypothesis is that transfer of the posterior interosseous nerve,which contains mainly motor fibers,to the ulnar or median nerve can innervate the intrinsic muscles of hands.The present study sought to investigate the feasibility of reconstruction of the deep branch of the ulnar nerve and the thenar branch of median nerve by transferring the extensor indicis proprius branch of the posterior interosseous nerve obtained from adult cadavers.The results suggested that the extensor indicis proprius branch of the posterior interosseous nerve had approximately similar diameters and number of fascicles and myelinated nerve fibers to those of the deep branch of ulnar nerve and the thenar branch of the median nerve.These confirm the feasibility of extensor indicis proprius branch of posterior interosseous nerve transfer for reconstruction of the deep branch of the ulnar nerve and the thenar branch of median nerve.This procedure could be a novel and effective method for the functional recovery of the intrinsic muscles of hands after ulnar nerve or median nerve injury.

Analysis of long-term outcomes of the posterior interosseous flap and compound flap

To analyze the long term outcomes of antebrachial flap using a pedicle of the d orsal interosseous artery Methods Ninety cases were followed up for 1-16 years, in which the indications, long te rm outcomes and dorsal aspect of the forearm were assessed retrospectively Results Eighty nine cases survived with satisfactory contour of the forearm and hand Conclusions Antebrachial flap using a pedicle of the dorsal interosseous artery is a n optimal method for repair of soft tissue defects in the hand

ENTRAPMENT OF POSTERIOR INTEROSSEOUS NERVE OF FOREARM REPORT OF 25 CASES

Of the 25 cases of entrapment, or compression syndrome of the posterior interosseous nerve of the forearm reported, 23 were treated surgically. The compressing or entrapping factors found during the operatious consisted of 14 sites in tendinous tissues, 12 in vessels, 6 in scar adhesions, and 3 unclear. Of 11 cases each had 2 or more compression sites. 19 patients underwent local decompression. And 4 cases had membranous and degenerated nerves resection and end-to-end anastomoses. Hypertrophy and inflammation appeared to be the main pathological changes in 10 cases. The causes and pathology are discussed and the early diagnosis and treatment emphasized.

Maisonneuve injury with no fibula fracture:A case report

BACKGROUND Ankle syndesmosis injury is difficult to diagnose accurately at the initial visit.Missed diagnosis or improper treatment can lead to chronic complications.Complete syndesmosis injury with a concomitant rupture of the interosseous membrane(IOM)is more unstable and severe.The relationship between this type of injury and Maisonneuve injury,in which the syndesmosis is also injured,has not been discussed in the literature previously.CASE SUMMARY A 16-year-old patient sustained left medial malleolar fracture,and the associated inferior tibiofibular syndesmotic instability was overlooked.After open reduction and internal fixation of the medial malleolar fracture,inferior tibiofibular syndesmosis diastasis with IOM rupture was detected by auxiliary imaging.Secondary surgical intervention was performed to reduce anatomically and fix with two trans-syndesmosis screws.Twelve weeks later,the screws were removed.At the 6-mo follow-up,the patient gained full range of motion of the ankle.CONCLUSION Complete syndesmosis injury with IOM rupture should be considered Maisonneuve-type injury.Open reduction and internal fixation could obtain good outcomes.

Reply: Anomalous Muscles in Carpal Tunnel Associated with Neurovascular Variation: Case Report and Brief Review

Gantzer’s muscle is an additional muscle in the forearm. We studied the incidence and the morphology of Gantzer’s muscle and its relation with neurovascular structures. However, unlike the previous suggestion by Eid et al., there is no significant difference in the frequency of the variations of these nerves whether Gantzer’s muscle is present or not.

Compound muscle action potential(CMAP)scan examination of paretic and contralateral muscles reveals motor unit alterations after stroke

This study presents a novel compound muscle action potential(CMAP)examination of motor unit changes in paretic muscle post stroke.CMAP scan of the first dorsal interosseous(FDI)muscle was performed bilaterally in 16 chronic stroke subjects.Various parameters were derived from the CMAP scan to examine paretic muscle changes,including CMAP amplitude,D50,step index(STEPIX)and amplitude index(AMPIX).A significant decrease in CMAP amplitude and STEPIX was observed in paretic muscles compared with contralateral muscles(CMAP amplitude:paretic(9.0±0.5)mV,contralateral(11.3±0.9)mV,P=0.024;STEPIX:paretic 101.2±7.6,contralateral 121.9±6.5,P=0.020).No significant difference in D50 and AMPIX was observed between the paretic and contralateral sides(P>0.05).The findings revealed complex paretic muscle changes including motor unit degeneration,muscle fiber denervation,reinnervation and atrophy,providing useful insights to help understand neuromuscular mechanisms associated with weakness and other functional deterioration post stroke.The CMAP scan experimental protocols and the applied processing methods are noninvasive,convenient,and automated,offering practical benefits for clinical application.

Distal median and radial nerve branch transfer techniques for upper extremity reanimation

Nerve transfers for peripheral nerve injuries have become increasingly popular over the past two decades.While techniques for ulnar nerve repair have been well-documented,more recent techniques for median and radial nerve branch reinnervation are still being explored.This review describes the outcomes of common and emerging techniques for reinnervation of the distal branches of the median and radial nerves.