Project description:The radial nerve and posterior interosseous nerve (PIN) are prone to injury at multiple sites. Electrodiagnostic (EDx) studies may only identify the most proximal lesion. Nerve ultrasound could augment EDx by visualizing additional pathology.This investigation was a retrospective examination of ultrasound and EDx from 26 patients evaluated for posterior cord/radial/PIN lesions.Eighteen of 26 patients had abnormalities on EDx (15 radial, 2 PIN, 1 posterior cord). Ultrasound identified 15 of 18 (83%) of the EDx abnormalities and provided additional diagnostic information. In 6 of 15 (40%) patients with EDx evidence of radial neuropathy, ultrasound identified both radial nerve enlargement and additional, unsuspected PIN enlargement (53% to 339% enlarged vs. unaffected side). Ultrasound also identified: nerve (dis)continuity at the trauma site (n = 8); and nerve tumor (n = 2; 1 with normal EDx).In radial neuropathy, ultrasound often augments EDx studies and identifies a second lesion in the PIN. Further studies are required to determine the etiology and significance of this additional distal pathology.
Project description:Although rare, posterior interosseous nerve (PIN) palsy can occur in patients with a closed proximal forearm fracture and may present in a delayed fashion after initial trauma. In this case series, three cases of posterior interosseous nerve (PIN) injury following proximal forearm fractures are presented and discussed. Our literature search yielded six studies concerning PIN injury in radial head/neck fractures and proximal forearm fractures. Out of a total of 8 patients, 7 patients were treated non-operatively and in one patient a PIN release was performed. One patient was lost to follow-up, all other 7 patients showed successful recovery. A treatment algorithm for PIN palsy after proximal forearm fractures is provided. Based on our experience and what we found in literature, it seems safe to treat PIN palsies conservatively.
Project description:ObjectiveWe sought to determine lesion sites and spatial lesion patterns in spontaneous anterior interosseous nerve syndrome (AINS) with high-resolution magnetic resonance neurography (MRN).MethodsIn 20 patients with AINS and 20 age- and sex-matched controls, MRN of median nerve fascicles was performed at 3T with large longitudinal anatomical coverage (upper arm/elbow/forearm): 135 contiguous axial slices (T2-weighted: echo time/repetition time 52/7,020 ms, time of acquisition: 15 minutes 48 seconds, in-plane resolution: 0.25 × 0.25 mm). Lesion classification was performed by visual inspection and by quantitative analysis of normalized T2 signal after segmentation of median nerve voxels.ResultsIn all patients and no controls, T2 lesions of individual fascicles were observed within upper arm median nerve trunk and strictly followed a somatotopic/internal topography: affected were those motor fascicles that will form the anterior interosseous nerve further distally while other fascicles were spared. Predominant lesion focus was at a mean distance of 14.6 ± 5.4 cm proximal to the humeroradial joint. Discriminative power of quantitative T2 signal analysis and of qualitative lesion rating was high, with 100% sensitivity and 100% specificity (p < 0.0001). Fascicular T2 lesion patterns were rated as multifocal (n = 17), monofocal (n = 2), or indeterminate (n = 1) by 2 independent observers with strong agreement (kappa = 0.83).ConclusionIt has been difficult to prove the existence of fascicular/partial nerve lesions in spontaneous neuropathies using clinical and electrophysiologic findings. With MRN, fascicular lesions with strict somatotopic organization were observed in upper arm median nerve trunks of patients with AINS. Our data strongly support that AINS in the majority of cases is not a surgically treatable entrapment neuropathy but a multifocal mononeuropathy selectively involving, within the main trunk of the median nerve, the motor fascicles that continue distally to form the anterior interosseous nerve.
Project description:BackgroundUlnar nerve injuries, especially high (proximal forearm) injuries, result in poor functional recovery. Peripheral nerve transfers have recently become a popular technique to augment nerve repairs and reduce the reinnervation distance before distal motor endplates irreversibly degenerate, leading to incomplete recovery.ObjectivesTo systematically review and analyse the recent literature regarding anterior interosseous nerve (AIN) to ulnar nerve transfers, including demographics, indications, outcomes, and complications.MethodsA search was performed using PubMed, MEDLINE, EMBASE, CINAHL, Scopus, and Cochrane databases using the keywords ulnar nerve, ulnar nerve injury, ulnar motor nerve, anterior interosseous nerve, anterior interosseous, AIN, nerve transfer, and end-to-side using a 3-component search along with the Boolean operators 'AND' and 'OR'.ResultsA total of 341 studies were retrieved using the search criteria. Sixteen studies met the inclusion criteria including 12 retrospective case series, 3 retrospective cohort studies, and a single randomised control trial. Nine studies involved supercharged end-to-side transfer (SETS), 6 involved end-to-end transfer (ETE), and only 1 study compared results between SETS and ETE transfers. A total of 269 patients underwent nerve transfers. In the ETE subgroup, the average time to nerve transfer was 7 months, with a mean follow-up period of 24.5 months. Post-procedure, 100% (37/37) patients recovered intrinsic function of BMRC ≥1, and the average recovery time was 3.6 months. A total of 85% of patients recovered intrinsic function of BMRC ≥3. In the SETS group, the average time to nerve transfer was 2.5 months. The average follow-up in this cohort was 13.2 months. About 93% (145/156) recovered the intrinsic function of BMRC ≥1, and the average time to recovery was 7 months. About 75% of patients recovered the intrinsic function of BMRC ≥3 in their first dorsal interossei.ConclusionAIN to ulnar nerve transfer carries low morbidity, and there is low quality evidence to suggest recovery of intrinsic muscle function compared with conventional primary repair techniques. The supercharged end-to-side transfer (SETS) seems to be more favourable compared with end-to-side transfer. Outcome measurements are highly variable amongst studies, making standardisation difficult. Results of further trials are highly anticipated in this exciting field of peripheral nerve surgery.
Project description:BackgroundInjuries to the ulnar nerve at or above proximal forearm level result in poor recovery despite early microsurgical repair, especially concerning the intrinsic motor function of the hand. To augment the numbers of regenerating axons into the targeted muscles, a nerve transfer of the distal branch of the median nerve, the anterior interosseous nerve, to the ulnar motor branch has been described.MethodsTwo patients with severe atrophy of the intrinsic hand muscles following an initial proximal ulnar nerve repair had surgery with an end-to-side transfer of the anterior interosseous nerve to the ulnar motor branch at the wrist level. Outcome and neuroplasticity were prospectively studied using questionnaires, clinical examinations, electroneurography, electromyography, somatosensory evoked potentials at pre nerve transfer and 3-, 12-, and 24-months post nerve transfer as well as navigated transcranial magnetic stimulation at pre nerve transfer and 3- and 12-months post nerve transfer.ResultsSuccessively improved motor function was observed. Complete reinnervation of intrinsic hand muscles was demonstrated at 12- to 24-months follow-up by electroneurography and electromyography. At the cortical level, navigated transcranial magnetic stimulation detected a movement of the hot-spot for the abductor digiti mini muscle, originally innervated by the ulnar nerve and the size of the area from where responses could be elicited in this muscle changed over time, indicating central plastic processes. An almost complete reinnervation of the pronator quadratus muscle was also observed.ConclusionBoth central and peripheral plastic mechanisms are involved in muscle reinnervation after anterior interosseous nerve transfer for treatment of proximal ulnar nerve injuries.
Project description:Surgical repair of distal biceps tendon rupture is a technically challenging procedure that has the potential for devastating and permanently disabling complications. We report two cases of posterior interosseous nerve (PIN) injury following successful biceps tendon repair utilizing both the single-incision and two-incision approaches. We also describe our technique of posterior interosseous nerve repair using a medial antebrachial cutaneous nerve graft (MABC) and a new approach to the terminal branches of the posterior interosseous nerve that makes this reconstruction possible. Finally, we advocate consideration for identification of the posterior interosseous nerve prior to reattachment of the biceps tendon to the radial tuberosity.
Project description:UnlabelledComplex hand trauma presents multifaceted problems for the surgeon. Soft tissue defects of the upper extremity must be carefully assessed to determine the most appropriate method of coverage of hand. In this article, the reversed posterior interosseous flap was used for coverage of the hand. The injured areas include: dorsum of the hand (10 cases), the wrist (3 cases) and the dorsal thumb (2 cases). All flaps survived completely and none exhibited venous compromise. All donor sites were skin grafted. The reversed posterior interosseous flap is a versatile option for coverage of moderate sized defects of the hand and is specifically indicated for coverage of injuries of the wrist, dorsal hand and dorsal thumb.Electronic supplementary materialThe online version of this article (doi:10.1007/s12593-011-0042-y) contains supplementary material, which is available to authorized users.
Project description:IntroductionDiabetic peripheral neuropathy (DPN) is a common complication of both type 1 (T1D) and type 2 diabetes (T2D). No cure for DPN is available, but several potential targets have been proposed for treatment. Heat shock proteins (HSPs) are known to respond to both hyper- and hypoglycemia. DPN can be diagnosed using electrophysiology and studied using peripheral nerve biopsies.AimThis study aimed to analyze the presence and patterns of HSPs in peripheral nerve biopsies from subjects with T1D, T2D, and healthy controls.MethodsPosterior interosseous nerves (PIN) from a total of 56 subjects with T1D (n = 9), with T2D (n = 24), and without diabetes (i.e., healthy controls, n = 23) were harvested under local anesthesia and prepared for quantitative mass spectrometry analysis. Protein intensities were associated with electrophysiology data of the ulnar nerve and morphometry of the same PIN, and differences in protein intensities between groups were analyzed.ResultsIn total, 32 different HSPs were identified and quantified in the nerve specimens. No statistically significant differences were observed regarding protein intensities between groups. Furthermore, protein intensities did not correlate with amplitude or conduction velocity in the ulnar nerve or with the myelinated nerve fiber density of PIN.ConclusionQuantitative proteomics can be used to study HSPs in nerve biopsies, but no clear differences in protein quantities were observed between groups in this cohort.
Project description:A thorough knowledge of the anatomy of the terminal branch of the posterior interosseous nerve (PIN) and its relationship to the anterior interosseous nerve (AIN) is essential in facilitating regional anesthetic blocks and planning surgical exposures for wrist surgery and arthrodesis of wrist and proximal row carpectomy. This cadaveric study focused on the anatomy and course of the PIN and its anatomical relationships at the distal forearm. Thirty embalmed cadaver forearms were dissected using microsurgical techniques. A structured pro forma was used to collect data. The PIN was consistently found in the fourth extensor compartment in all specimens. The last motor branch was given off 46.9 ± 8.4 mm (mean ± standard deviation) from the most proximal part of the ulnar head. The AIN was found lying consistently on the anterior aspect of the interosseous membrane, being on average 2.8 ± 0.2 mm (mean ± standard deviation) from the PIN. This knowledge will facilitate the planning of diagnostic and therapeutic procedures associated with the wrist.