Andrés A. Maldonado

Free Functioning Gracilis Muscle Transfer versus Intercostal Nerve Transfer to Musculocutaneous Nerve for Restoration of Elbow Flexion after Traumatic Adult Brachial Pan-Plexus Injury.

Background: After complete five-level root brachial plexus injury, free functional muscle transfer and intercostal nerve transfer to the musculocutaneous nerve are two potential reconstructive options for elbow flexion. The aim of this study was to determine the outcomes of free functional muscle transfer versus intercostal nerve–to–musculocutaneous nerve transfers with respect to strength. Methods: Sixty-two patients who underwent free functional muscle transfer reconstruction or intercostal nerve–to–musculocutaneous nerve transfer for elbow flexion following a pan-plexus injury were included. The two groups were compared with respect to postoperative elbow flexion strength according to the British Medical Research Council grading system; preoperative and postoperative Disabilities of the Arm, Shoulder, and Hand questionnaire scores. Results: In the free functional muscle transfer group, 67.7 percent of patients achieved M3 or M4 elbow flexion. In the intercostal nerve–to–musculocutaneous nerve transfer group, 41.9 percent of patients achieved M3 or M4 elbow flexion. The difference was statistically significant (p < 0.05). Changes in Disabilities of the Arm, Shoulder, and Hand questionnaire scores were not statistically significant. Average time from injury to surgery was significantly different (p < 0.01) in both groups. The number of intercostal nerves used for the musculocutaneous nerve transfer did not correlate with better elbow flexion grade. Conclusions: Based on this study, gracilis free functional muscle transfer reconstruction achieves better elbow flexion strength than intercostal nerve–to–musculocutaneous nerve transfer for elbow flexion after pan-plexus injury. The role of gracilis free functional muscle transfer should be carefully considered in acute reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Free Functioning Gracilis Muscle Transfer for Elbow Flexion Reconstruction after Traumatic Adult Brachial Pan-Plexus Injury: Where Is the Optimal Distal Tendon Attachment for Elbow Flexion?

Background: Reconstruction after pan-plexus root avulsions often includes gracilis free functioning muscle transfer. For elbow flexion reconstruction, the free functioning muscle transfer distal tendon is inserted into the biceps tendon or more distally (i.e., flexor digitorum profundus/flexor pollicis longus tendons) for combined elbow and finger flexion; the theoretical drawback of the latter approach is weaker elbow flexion. The authors compared elbow flexion strength with a biceps tendon versus a flexor digitorum profundus/flexor pollicis longus tendon attachment to determine which insertion point resulted in better elbow flexion. Methods: Thirty-nine patients underwent free functioning muscle transfer with either a biceps tendon or a distal attachment. Groups were compared on postoperative elbow flexion strength, preoperative and postoperative Disabilities of the Arm, Shoulder, and Hand questionnaire scores, range of motion, and other surgical and demographic characteristics. A biomechanical analysis simulating different tendon attachments determined which reconstruction resulted in optimal elbow flexion mechanics. Results: Distal tendon attachment was associated with M3 or M4 elbow flexion and greater range of motion compared with the biceps tendon attachment (p < 0.05). There were no statistically significant improvements in Disabilities of the Arm, Shoulder, and Hand questionnaire scores. Biomechanical analysis demonstrated that all distal tendon attachments studied generated a 15 to 30 percent greater torque compared with the biceps tendon attachment; this was true for attachments either at the flexor digitorum profundus/flexor pollicis longus tendon, or directly at the radius at 10 cm or 15 cm from the elbow axis of rotation. Conclusions: The flexor digitorum profundus/flexor pollicis longus tendon attachment of the gracilis free functioning muscle transfer distal tendon was superior in achieving elbow flexion strength. Patients with only elbow flexion reconstruction may also benefit from a flexor digitorum profundus/flexor pollicis longus tendon attachment or from a more distal attachment to the radius. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

ANATOMICAL STUDY OF THE AXILLARY NERVE: DESCRIPTION OF A SURGICAL BLIND ZONE

Background: The aim of this study was to quantify the length of the axillary nerve that is able to be dissected through a standard anterior (deltopectoral) and posterior approach. The authors hypothesize that a segment of the axillary nerve cannot be reached using both approaches simultaneously. Methods: Axillary nerves of five frozen cadavers were dissected using an anterior and posterior approach. A first surgical clip marked the most visible distal part of the nerve from the deltopectoral approach; a second surgical clip marked the most proximal part from the posterior approach. The two surgical clips were localized with a shoulder radiograph. The authors performed measurements of the different axillary nerve segments. Results: In all specimens, there were three zones of the axillary nerve: zone A (anterior), the nerve segment from the origin of the axillary nerve to the first surgical clip, located at the level of the triangle formed by the subscapularis muscle (medial), conjoined tendon (lateral), and axillary fat (inferior); zone B (blind), the nerve segment not reachable through both approaches, from the first to the second surgical clip; and zone C (circumflex), the nerve segment from the second surgical clip (located at the level of the quadrilateral space) to entry into the deltoid muscle. The mean length of the blind zone was 1.6 cm. This blind zone was found 1 to 2 cm from the glenohumeral joint. Conclusion: The authors have described a segment of the axillary nerve that cannot be evaluated through anterior and posterior combined approaches.

Reinterpretation of Electrodiagnostic Studies and Magnetic Resonance Imaging Scans in Patients with Nontraumatic “Isolated” Anterior Interosseous Nerve Palsy

Background: Different hypotheses have been proposed for the pathophysiology of anterior interosseous nerve palsy: compression, fascicular constriction, or nerve inflammation (Parsonage-Turner syndrome). The authors hypothesized that critical reinterpretation of electrodiagnostic studies and magnetic resonance imaging scans of patients with a diagnosis of anterior interosseous nerve palsy could provide insight into the pathophysiology and treatment. Methods: A retrospective review was performed of all patients with a diagnosis of nontraumatic anterior interosseous nerve palsy and an upper extremity magnetic resonance imaging scan. The original electrodiagnostic study and magnetic resonance imaging scan reports were reinterpreted by a neuromuscular neurologist and musculoskeletal radiologist, respectively, both blinded to the authors’ hypothesis. Results: Sixteen patients met the inclusion criteria as having “isolated” anterior interosseous nerve palsy. Physical examination revealed weakness in muscles not innervated by the anterior interosseous nerve in five cases (31 percent), and electrodiagnostic studies showed abnormalities not related to the anterior interosseous nerve in nine of 15 cases (60 percent). In all cases, reinterpretation of the magnetic resonance imaging scans demonstrated atrophy in at least one muscle not innervated by the anterior interosseous nerve and did not reveal any evidence of compression of the anterior interosseous nerve. Conclusions: All patients in the authors’ series with presumed isolated anterior interosseous nerve palsy had magnetic resonance imaging evidence of a more diffuse muscle involvement pattern, without any radiologic signs of nerve compression of the anterior interosseous nerve branch itself. These data strongly support an inflammatory pathophysiology.

Lateral pectoral nerve transfer for spinal accessory nerve injury

Spinal accessory nerve (SAN) injury results in loss of motor function of the trapezius muscle and leads to severe shoulder problems. Primary end-to-end or graft repair is usually the standard treatment. The authors present 2 patients who presented late (8 and 10 months) after their SAN injuries, in whom a lateral pectoral nerve transfer to the SAN was performed successfully using a supraclavicular approach.

“Isolated long thoracic nerve palsy”: More than meets the eye

INTRODUCTION Two main hypotheses have been proposed for the pathophysiology of long thoracic nerve (LTN) palsy: nerve compression and nerve inflammation. We hypothesized that critical reinterpretation of electrodiagnostic (EDX) studies and MRIs of patients with a diagnosis of non-traumatic isolated LTN palsy could provide insight into the pathophysiology and, potentially, the treatment. MATERIAL AND METHODS A retrospective review was performed of all patients with a diagnosis of non-traumatic isolated LTN palsy and an EDX and brachial plexus or shoulder MRI studies performed at our institution. The original EDX studies and MR examinations were reinterpreted by a neuromuscular neurologist and musculoskeletal radiologist, respectively, both blinded to our hypothesis. RESULTS Seven patients met the inclusion criteria as having a non-traumatic isolated LTN palsy. Upon reinterpretation, all of them were found to have findings not consistent with an isolated LTN. On physical examination, three of them (43%) presented with weakness in muscles not innervated by the LTN. Four of them (57%) had additional EDX abnormalities beyond the distribution of the LTN. Five of them (71%) had MRI evidence of enlargement of nerves or denervation atrophy of muscles outside the innervation of the LNT, without evidence of compression of the LTN in the middle scalene muscle. CONCLUSION In our series, all 7 patients, originally diagnosed as having an isolated LTN, on reinterpretation, were found to have a more diffuse muscle/nerve involvement pattern, without MR findings to suggest nerve compression. These data strongly support an inflammatory pathophysiology.

Proposed surgical technique to facilitate targeted reinnervation of the infraspinatus: A cadaveric feasibility study: Nerve Transfer for Infraspinatus Reinnervation

Restoration of shoulder lateral rotation remains a significant challenge following brachial plexus injury. Transfer of the accessory nerve to suprascapular nerve (SSN) has been widely performed, although with generally poor outcomes for lateral rotation. A recent report suggested a selective infraspinatus reinnervation technique using a radial nerve branch for SSN transfer. This cadaveric study was performed in 7 specimens (14 shoulders). We present technical modifications to achieve additional length to the recipient nerve (suprascapular) that would facilitate direct repair. Key elements of the technique are (1) isolation of the SSN immediately distal to its motor branch to supraspinatus near the superior transverse scapular ligament; and (2) delivery of the transected SSN through the spinoglenoid notch and deep to the infraspinatus for emergence in the infraspinatus‐teres minor interval. Nerve overlap of at least 21 mm was observed in all 14 dissected shoulders between the harvested SSN and radial nerve branches. The mean nerve overlap between harvested branches was 26 mm (range 21–32 mm). The mean harvested SSN length was 59 mm (range 46–80 mm). The mean length of the harvested radial nerve branch was 72 mm (range 65–85 mm). No measurements were significantly different between left and right shoulders or between males and females (smallest P value = 0.1249). Nerve diameter of the two harvested branches was judged to be appropriately compatible for surgical coaptation in all 14 dissected shoulders. We present a variation on a described technique to increase recipient suprascapular nerve length. Additional length of the recipient nerve is achieved through utilization of a more proximal dissection of the suprascapular nerve near the level of the superior transverse scapular ligament and delivering the nerve through the teres minor‐infraspinatus interval. These surgical modifications are of clinical interest when selective reinnervation of the infraspinatus muscle is considered. We believe such a targeted approach can potentially increase shoulder lateral rotation function. Clin. Anat. 32:131–136, 2019.

Five Operations that give the best results after brachial plexus injury

Summary: Treatment of brachial plexus injuries has improved slowly over the past 45 years. Changes in strategy, techniques, microsurgical equipment, and technology have expanded the surgical options for reconstructing these life-altering, highly complex injuries. The surgical techniques available include neurolysis, nerve repair, nerve grafting, nerve transfers, tendon transfer, muscle transfer, and other soft- and bony-tissue procedures. In this article, the authors have selected five surgical procedures (i.e., Oberlin procedure, Leechavengvongs procedure, free functional muscle transfer, radial nerve tendon transfers, and C5-C6 nerve grafting in obstetric birth palsy) that have consistently yielded good results in patients who require surgical reconstruction.

Delayed compression of the common peroneal nerve following rotational lateral gastrocnemius flap: case report

The authors present a case of delayed peroneal neuropathy following a lateral gastrocnemius rotational flap reconstruction. The patient presented 1.5 years after surgery with a new partial foot drop, which progressed over 3 years. At operation, a fascial band on the deep side of the gastrocnemius flap was compressing the common peroneal nerve proximal to the fibular head, correlating with preoperative imaging. Release of this fascial band and selective muscle resection led to immediate improvement in symptoms postoperatively.