Gonzalo Bonilla

Transfer of flexor carpi ulnaris branches to selectively restore AIN function in median nerve sections: Anatomical feasibility study and case report

Background: In recent years, distal nerve transfers have become a valid tool for nerve reconstruction. Though grafts remain the gold standard for proximal median nerve injuries, a new distal transfer of flexor carpi ulnaris branches of the ulnar nerve to selectively restore anterior interosseous nerve function, concomitant with median nerve graft repair, could enhance outcomes. The objective of this paper is to anatomically analyze a technique to selectively reinnervate the thumb and index flexors. Methods: Both the median and ulnar nerves were dissected in 10 cadavers. First and second branches to the flexor carpi ulnaris (FCU) were measured for length at its emergence from the ulnar nerve, and for width. The emergence of the AIN, just proximal to the arch of the flexor digitorum superficialis, was dissected, and the distance measured from this point to its motor entry at the long flexor pollicis and its branch to the long index flexor. A tensionless repair was performed between one FCU branch and the AIN. Results: The mean AIN length was 32.3±8.20 mm and width 2.4±0.49 mm. The first branch from the ulnar nerve to the FCU measured 20.8±2.04 mm and 1.52±0.44 mm, while the second, more distal branch measured 24.3±6.71 and 1.9±0.17 mm, respectively. In all dissections, it was possible to contact both the proximal and distal branches of the ulnar nerve to the FCU with the distal stump of the divided AIN, with no tension or need for interposed nerve grafts. Conclusions: Though proximal reconstruction remains the gold standard, new distal nerve transfer techniques may improve outcomes.

Age as a Predictor of Long-Term Results in Patients with Brachial Plexus Palsies Undergoing Surgical Repair

BACKGROUND Among other factors, like the time from trauma to surgery or the number of axons that reach the muscle target, a patients age might also impact the final results of brachial plexus surgery. OBJECTIVE To identify (1) any correlations between age and the 2 outcomes: elbow flexion strength and shoulder abduction range; (2) whether childhood vs adulthood influences outcomes; and (3) other baseline variables associated with surgical outcomes. METHODS Twenty pediatric patients (under age 20 yr) who had sustained a traumatic brachial plexus injury were compared against 20 patients, 20 to 29 yr old, and 20 patients, 30 yr old or older. Univariate, univariate trend, and correlation analyses were conducted with patient age, time to surgery, type of injury, and number of injured roots included as independent variables. RESULTS A statistically significant trend toward decreasing mean strength in elbow flexion, progressing from the youngest to oldest age group, was observed. This linear trend persisted when subjects were subdivided into 4 age groups (<20, 20-29, 30-39, ≥40). There were no differences by age group in final shoulder abduction range or the percentage achieving a good shoulder outcome. CONCLUSION Our data suggest that age is somehow linked to the outcomes of brachial plexus surgery with respect to elbow flexion, but not shoulder abduction strength. Increasing age is associated with steadily worsening elbow flexion outcomes, perhaps indicating the need for earlier surgery and/or more aggressive repairs in older patients.

Phrenic to musculocutaneous nerve transfer for traumatic brachial plexus injuries: analyzing respiratory effects on elbow flexion control

OBJECTIVEIn this study, the authors sought to identify the relationship between breathing and elbow flexion in patients with a traumatic brachial plexus injury (TBPI) who undergo a phrenic nerve (PN) transfer to restore biceps flexion. More specifically, the authors studied whether biceps strength and the maximal range of active elbow flexion differ between full inspiration and expiration, and whether electromyography (EMG) activity in the biceps differs between forced maximum breathing during muscular rest, normal breathing during rest, and at maximal biceps contraction. All these variables were studied in a cohort with different intervals of follow-up, as the authors sought to determine if the relationship between breathing movements and elbow flexion changes over time.METHODSThe British Medical Research Council muscle-strength grading system and a dynamometer were used to measure biceps strength, which was measured 1) during a maximal inspiratory effort, 2) during respiratory repose, and 3) after a maximal expiratory effort. The maximum range of elbow flexion was measured 1) after maximal inspiration, 2) during normal breathing, and 3) after maximal expiration. Postoperative EMG testing was performed 1) during normal breathing with the arm at rest, 2) during sustained maximal inspiration with the arm at rest, and 3) during maximal voluntary biceps contraction. Within-group (paired) comparisons, and both correlation and regression analyses were performed.RESULTSTwenty-one patients fit the study inclusion criteria. The mean interval from trauma to surgery was 5.5 months, and the mean duration of follow-up 2.6 years (range 10 months to 9.6 years). Mean biceps strength was 0.21 after maximal expiration versus 0.29 after maximal inspiration, a difference of 0.08 (t = 4.97, p < 0.001). Similarly, there was almost a 21° difference in maximum elbow flexion, from 88.8° after expiration to 109.5° during maximal inspiration (t = 5.05, p < 0.001). Involuntary elbow flexion movement during breathing was present in 18/21 patients (86%) and averaged almost 20°. Measuring involuntary EMG activity in the biceps during rest and contraction, there were statistically significant direct correlations between readings taken during normal and deep breathing, which were moderate (r = 0.66, p < 0.001) and extremely strong (r = 0.94, p < 0.001), respectively. Involuntary activity also differed significantly between normal and deep breathing (2.14 vs 3.14, t = 4.58, p < 0.001). The degrees of involuntary flexion were significantly greater within the first 2.6 years of follow-up than later.CONCLUSIONSThese results suggest that the impact of breathing on elbow function is considerable after PN transfer for elbow function reconstruction following a TBPI, both clinically and electromyographically, but also that there may be some waning of this influence over time, perhaps secondary to brain plasticity. In the study cohort, this waning impacted elbow range of motion more than biceps muscle strength and EMG recordings.

Clinical Follow-Up

Analysing the results of nerve repair is very important to compare the effectiveness of different strategies and, thus, develop standardized guidelines for the management and treatment of nerve injuries.

Integrated Pain-Severity Scale and different kinds of pain in brachial plexus injuries

Dear Editor, We greatly appreciate the comments by Aly M, Saitoh Y et al. regarding our article “Pain and Brachial Plexus Lesions: Evaluation of Initial Outcomes after Reconstructive Microsurgery and Validation of a New Pain Severity Scale”. We do absolutely agree with the differences in outcome and prognoses that continuous versus shooting pain have, as pointed out by these authors. Nevertheless, we do not agree to separately consider both kinds of pain in the same scale. It s important to point out that the main purpose of our scale was to provide a tool to objectively determine the quantity of pain that a certain patient refers during its treatment, and not to distinguish between both kinds of pain. In the “pain frequency” item, the purpose was not to differentiate between continuous and paroxysmal pain, but to establish the number of times during 1 day that a patient refers the pain. If we quantified separately shooting or continuous pain in an equivalent numeric scale for both items, we could find some patients with predominantly one or the other type of pain, and a similar score in our scale, not reflecting the differences pointed out by Aly M et al. If we, by contrary, would have considered a different punctuation to the separately considered continuous and shooting pain (e.g., giving more points to continuous pain, reflecting its worst prognosis), we could find some patients with a middle or high score on the scale having a mild continuous pain, and a similar score in a patient with very frequent and invalidating paroxysmal pain. In conclusion, we preferred not to consider separately different kinds of pain in our Integrated Pain-Severity Scale. This might help to objectively analyse these different pain syndromes in terms of severity, prognosis and outcome, a very interesting challenge that mostly still remains to be done.