The ulnar nerve as vascularized nerve transplant. Part I: Anatomy: arterial vascular supply

Epineurotomy for leprous, high ulnar neuropathy: defining a safe corridor based on the epineural vascular anatomy

BACKGROUND

Leprous neuropathy is treatable but still a source of disability worldwide. Multidrug therapy (MDT) and oral steroids are the main stay of treatment. Ulnar nerve, at the elbow, is commonly involved. Nerve decompression may be required in selected cases by an epineurotomy (internal neurolysis). The preferred surface of ulnar nerve for performing this procedure to minimize iatrogenic vascular compromise is a matter of debate.

QUESTIONS/PURPOSES

We describe the epineural vessel arrangement on the medial and lateral surface of ulnar nerve around the medial epicondyle while performing epineurotomy for leprous neuropathy.

METHODS

We enrolled patients of symptomatic leprous ulnar neuropathy of less than one year duration on MDT that did not respond to steroids, for surgical decompression. Ten patients underwent epineurotomy of ulnar nerves (N = 11) around medial epicondyle. The epineural vessels were classified as per Sunderland's classification of arteriae nervorum. The number of epineural vessels was assessed on the medial and lateral surface of the ulnar nerve adjoining the medial epicondyle. The epineurotomy incision was placed over the surface of ulnar nerve having relatively less vessels.

RESULTS

The mean number of epineural vessels on the medial surface was 9.72 (range; 7-14) and on the lateral surface were 4.72 (range; 3-6). The average number of vessels per cm² of the medial and lateral surface of the nerve was 0.94 and 0.48, respectively. The most common type of epineural vessel was type 3 on both medial and lateral surface of the nerve. Lateral epineurotomy was performed in all 11 cases. All the patients had relief from neuropathic pain. The mean VAS score improved from 3.20 ± 0.89 to 0.50 ± 0.34 at 2 years follow-up (p = 0.02). The mean motor score improved from 9.31 ± 4.12 to 15.42 ± 3.10 and sensory score improved from 40.0 ± 30.70 to 85 ± 9.90 at two years follow-up (p < 0.01).

CONCLUSION

Lateral surface (facing the medial epicondyle) of ulnar nerve has a lesser density of epineural vessels in comparison to its medial (subcutaneous) surface.

CLINICAL RELEVANCE

This anatomical understanding may be helpful in minimizing the iatrogenic vascular compromise of ulnar nerve while performing its epineurotomy around the medial epicondyle for leprous neuropathy. The findings may be extrapolated to other clinical indications of epineurotomy of ulnar nerve, for example, in cubital tunnel syndrome, traumatic ulnar neuroma in continuity, and benign ulnar nerve tumors.

Transfer of Pedicled Musculocutaneous Latissimus Dorsi Flap for Restoration of Shoulder Contour After Neurogenic Atrophy

Neurogenic atrophy of the deltoid muscle due to brachial plexus injury will lead to a disfiguring deformity of the shoulder contour, apart from the functional deficit. When there is no possibility for functional restoration of the shoulder movement, this contour defect will become the patient's major concern. We present a new method in which the ipsilateral latissimus dorsi muscle was used as a pedicled musculocutaneous flap to augment the shoulder contour in 3 patients. In all patients, there was a concomitant lesion to the thoracodorsal nerve, with subsequent palsy of the latissimus dorsi muscle. Therefore, donor-site morbidity was minimal. The final esthetic appearance was pleasing, and the patient satisfaction was quite high.

The extraneural and intraneural arterial anatomy of the ulnar nerve at the elbow

The purpose of this report was to investigate the vascular anatomy of the ulnar nerve at the elbow with a technique of combined India ink and latex injection followed by nondissection chemical debridement. Twenty-two fresh human cadaveric arms were injected with India ink to stain the intraneural microcirculation followed immediately by latex injection and chemical debridement for study of the extraneural vascularization. After clearing with a modified Spalteholtz technique, the intraneural blood supply was studied in 10 of the specimens. The findings demonstrated a consistent but segmental extraneural and intraneural vascular supply from the superior ulnar collateral, inferior ulnar collateral, and posterior ulnar recurrent arteries. No identifiable direct anastomosis was seen between the superior ulnar collateral and posterior ulnar recurrent arteries in 20 of 22 arms. The inferior ulnar collateral artery provided the only direct vascularization to the nerve in the region just proximal to the cubital tunnel. Although the clinical importance of maintaining specific arterial sources to the ulnar nerve has not been determined, these anatomic findings indicate that the arterial contribution from the inferior ulnar collateral artery may be more important than appreciated previously.

Brachial plexus surgery: our concept of the last twelve years

In patients with brachial plexus injuries restoration of complete function is seldom seen. The diagnosis is a clinical one; investigations such as MRI or myelography are not sufficiently reliable to base surgical indications on them. Surgery has to be performed within the first six months after the trauma. The surgical procedure firstly includes an exact intraoperative definition of the extent of the lesion. Depending on the type of the lesion, microsurgical neurolysis, nerve grafting, or reneurotization is performed. When regeneration is complete, secondary operations may follow if necessary as part of our integrated concept. The spectrum of secondary operations in our patients includes arthrodesis, tenodesis, tendon transfers, muscle transfers, and free neurovascular tissue transfer. In selected cases with extensive lesions a bifunctional latissimus dorsi transfer allows restoration of minimal grip with simultaneous elbow flexion. Our concept includes a series of hierarchical steps: 1. Diagnosis and indication 2. Nerve repair 3. Intensive physiotherapy, control in intervals 4. Secondary operations--if necessary 5. Intensive physiotherapy 6. Ergotherapy, orthosis In the last 12 years 362 patients with brachial plexus lesions have been operated on in our clinic. In these patients we performed 104 neurolyses, 126 nerve grafting procedures, 87 reneurotizations, and 191 secondary operations in 96 patients. Only the combination of nerve repair with both conventional and newer methods of tendon and muscle transfers can restore the maximum function for the individual situation.

The extrinsic blood supply of the ulnar nerve at the elbow: an anatomic study

The extrinsic vasculature of the ulnar nerve as it relates to the treatment of cubital tunnel syndrome has not previously been described in detail. For a study of the anatomy, 18 fresh-frozen cadaver upper limbs were dissected after intra-arterial injection of latex. Two major pedicles were present in all 18 specimens--the superior ulnar collateral artery proximally and the posterior ulnar recurrent artery distally. A single minor pedicle, the inferior ulnar collateral artery, was present in 5 of 18 specimens. Total vessel length as well as distance to the medial epicondyle for the extrinsic arteries was measured. On the basis of these anatomic dissections, it is suggested that the extrinsic vascular supply can be preserved during anterior transposition of the ulnar nerve, even after extensive mobilization of the nerve.

Advances in peripheral nerve repair in emergency surgery of the hand

The development of microsurgical techniques has changed the surgical treatment of severe hand injuries over the last 25 years. Not only has the repair of vessels by microvascular surgery brought new possibilities of treatment, but the results in repair or peripheral nerves have been improved by the use of new microsurgical techniques, such as perineural suture and interfascicular nerve grafts. The use of vascularized nerve grafts in multiple digit amputations has been a further new idea in emergency hand surgery. The operative treatment of lesions of the brachial plexus has become possible. Nevertheless, the traditional secondary operations such as tendon and muscle transfers are necessary in order to reach an optimal functional reconstruction following nerve injuries.

Progress in peripheral nerve reconstruction

The development of peripheral nerve surgery over the past 15 years has been fascinating to watch. Significant improvements have been achieved by the wide application of techniques which were developed before this period. New approaches may revolutionize the tactics of nerve repair in the near future.

Single stage reconstruction of a large tibial defect using a free vascularised osteomyocutaneous ulnar transfer

We present the case of a young man with 13 cm of bone and soft-tissue loss in the tibia and a severe traction injury of the brachial plexus. A free vascularised composite transfer of the bone and soft tissues of the ulnar side of the forearm was undertaken to reconstruct the defect. Bony union was achieved after a year and was followed by complete functional recovery of the lower limb.