Vascularized Transposition of the Ulnar Nerve in Entrapment Syndrome at the Elbow
by Messina Antonino*
Former Chief Orthopaedic Surgeon and Founder of the Hand Surgery Centre and Microsurgery Laboratory of the Orthopaedic Trauma Centre (C. T. O.), Turin, Italy
*Corresponding author: Messina Antonino, Former Chief Orthopaedic Surgeon and Founder of the Hand Surgery Centre and Microsurgery Laboratory of the Orthopaedic Trauma Centre (C. T. O.), Turin, Italy
Received Date: 14 August, 2023
Accepted Date: 16 October, 2023
Published Date: 19 October, 2023
Citation: Antonino M (2023) Vascularized Transposition of the Ulnar Nerve in Entrapment Syndrome at the Elbow. Arch Surg 3: 118 https://doi.org/10.29011/AOS-118.000018
Background and Purpose: The surgical treatment of Cubital Tunnel Syndrome still hasunsatisfactory results due mainly to arteriovenous ischemia of the nerve in the Epitrochlear Canal. The purpose of our biological procedure is to restore the vascularization of the nerve, transposed together with its vascular pedicle anteriorly to epicondyle, to immediately reactivate the axonal conduction of the Ulnar Nerve and thereby improve clinical results.
Methods: From 1987 to 2022, a vascularized Anteposition was performed on 87 limbs for UlnarNerve Entrapment Syndrome at the elbow in 82 patients.
Results: Fifty-seven Patients returned for follow-up, 52 Patients obtained excellent and good resultsand effective recovery of sensibility and muscular activity; the electromyographic examination showed many positive changes in the SCV and MCV with increased nerve conduction velocity. Patients with fair results (5 Patients) showed worthwhile recovery of the hand but they recorded many sensory and motor disturbances already present before the operation, even if more attenuated.
Conclusions: Our surgical technique of Vascularised Anteposition of the Ulnar Nerve at the Elbowis able to resolve the mechanical aspect of the chronic neuritis of the Ulnar Nerve at the Elbow but also (preserving its vascularity) the biological aspect of its nutrition. The procedure, allowing effective, quick recovery of hand function in most of the patients of our Study-an improvement in all of them-is a step forward in the treatment of this disease.
Keywords: Biological ulnar nerve transposition; Ulnar nerve entrapment; Ulnar nerve palsy; Vascularized anteposition cubital nerve; Vascularized ulnar nerve transposition
Subcutaneous Anteposition Technique at the Elbow has been proposed from 1898 (125 years ago as of the time of writing) by Curtis B,F. for Cubital nerve pathologies.
To day the only more important and innovative surgical methods for treating this condition in the world are :
- Traumatic ulnar neuritis:Transplantation of the nerve, Curtis B,F.1898 (125 years ago) ;
- The Epitrochlear Canal Opening-Buzzard E,F, 1922 (101 years ago) ;
- The Submuscular Transposition-Learmonth G,R.1942 (81 years ago) ;
- The Intramuscular transposition---Gay J.R,and Love J.G
(1947) (76 years ago) ;
- The Epitrochlear removal--King 1950 (73 years ago) ;
- La Trasposizione microchirurgica del Nervo Ulnare e del suo peduncolo vascolare nella Sindrome compressivo-paretica canalicolare del Gomito (Microsurgical Transposition of the Ulnar Nerve and its Vascular Pedicle in compressive-paretic canalicular syndrome of the elbow)--- Messina A. 1991 (32 years ago) . Although the aetiology of this pathology does not seem to be important, many investigations have been made into its definition [7,8] giving only generic titles such as: “cubital nerve syndrome,” “cubital tunnel entrapment,” “ulnar nerve entrapment,” “ulnar nerve compression,” “cubital tunnel syndrome,” etc. McGowan  distinguished three degrees of lesion severity. However, this this classification, which useful pre-operatively, is not exhaustive for the clinical assessment of the results in the postoperative evaluation.
Foster RJ and Edshage S. conducted a thorough study on Subcutaneous, Submuscular and Intramuscular intervention stating that the overall results are the same above 90%; . Adelaar R,S, et al. state that there is no statistical difference in results between subcutaneous and submuscular transposition . In the King’s Epitrochlear removal, although the nerve remains adjacent to its artery, many potential disadvantages can come [12,13]. Holtzman R,N, et al. suspect that ulnar nerve neuropathy may depend on compression associated with ischaemia or hypoxia of the nerve in the cubital canal [14,15]. Many studies conducted by different authors show compression causes ischaemia and oedema, resulting in deposition of collagen in the epineurium and endoneurium, and underline the importance of the extrinsic blood supply [16-23]. Lastly, the procedure of simple decompression of the ulnar nerve without transposition aims to preserve the nerve’s vascularity, but does not remove the traction-tension during elbow flexion with continuous trauma and possible subluxation of the nerve.
From the analysis of clinical and operative literature, all simple neurolysis, neurolysis and anteposition, neurolysis and transposition performed for different types and stages of clinical pathology showed variable outcomes: some resulted in good functional recovery, others in slight or no improvement or some deterioration and some-time secondary persistent hyperpathy [16,17]. In our experience and in the majority of studies, ulnar nerve neuritis at the elbow is due to continuous traction of the ulnar nerve during elbow flexion which produces a perineural fibrous reactivity, adhesions, and canalicular fibrosis which over time also affects the ligament of Osborne, and strangles it together with its vascular pedicle [11,14,18]. Anteposition procedures currently in use today by performing neurolysis of the entire extracompartmental segment of the nerve at the elbow isolates and disconnects its longitudinal and epineural vascularity up to 10-15 cm long. The disconnection of the nerve nutrition (in addition to the neuritis pathology) causes impairment of axonal conduction, lengthening of the restoration of the sensory-motor fascicles, secondary dysesthesias and functional failure. So too can it often be observed that chronic compression results in altered epi and endonervial vascularisation of the ulnar nerve, and that in some cases the nerve thickness together with its vascular bundle was severely reduced to an hourglass shape by Osborne’s ligament. In my research published in 1995 by J. H. Surg, I was the first to show in chronical neuritis by mean of an intraoperative arteriography, the blockage of the collateral artero-venous blood flow of the Ulnar Nerve at the Elbow before the opening of the epitrochlear canal and the immediate restoration of the vascularization of the compressed Ulnar Nerve, immediately after the opening of Osborne’s ligament .
The aim of the study, then, is to highlight and update the records and technical details of the procedure. Solving the mechanical aspect of compression in the treatment of ulnar nerve entrapment syndrome at the elbow, this Procedure also represents a biological method: the nerve together with its vascular pedicle preserving its blood supply is transposed anteriorly to the epitrochlear canal, thus enhancing axonal recovery of the nerve. This ensures better functional recovery in all the various degrees of severity and complications of this canalicular pathology in our care [6,18].
Materials and Methods Operative Technique
A longitudinal curved incision is performed posterior to the epitroclear epicondyle, extending for 15 centimeters below the condyle. The ulnar nerve and its vascular bundle are inspected above the condyle and dissected proximally by opening the fibroaponeurotic sheath and the medial intermuscular septum (Figure 1). The ulnar nerve, together with its vascular bundle coming from brachial artery and composed of the ulnar collateral artery and of one or two satellite veins, is dissected and mobilized distally to free it and mobilized under optical magnification [6,17,18]; the use of magnifying glasses is only necessary during vascular time (Figure 2).
After opening of Osborne’s ligament a longitudinal incision of the epineurium is performed on the opposite side of longitudinal collateral blood supply if there exists any constriction of the nerve (MacGowan’s grade 3). The space between the humeral and ulnar insertions of the flexor carpi ulnaris is split and enlarged distally, so that the ulnar nerve together with its vascular bundle after anterior submuscular or intramuscular transposition [3,4] will not be sharply angulated as it enters this muscle group ; the motor innervation of the flexor carpi ulnaris must be protected (Figure 2). Immediately after removal of Esmach’s band, the nerve trunk, transposed by intramuscular transposition (Gay and Love) , regains its vascularity and becomes red throughout its entire extracompartmental length (Figure 3). The ensuing operative technique of anterior submuscular or intramuscular transposition is essentially that described by Learmonth J.R. (1942) . The elbow is now extended and flexed to assure that there is free movement and no kinking of the nerve and its vascular collateral bundle from the medial intermuscular septum anterior to the epicondyle. The wound is then closed and the limb immobilized in a posterior splint for two weeks with the elbow in 120 degrees of flexion. Range-of-motion exercises are then initiated to reach complete articular motion.
Figure 1: Classic arcuate skin incision at the Elbow for Vascularised Anteposition Technique of the Ulnar Nerve at the Elbow since 1987.“ In addition to the mechanical effect of Anteposition, there is the advantage of the biological effect for nerve fascicles nutrition and early restoration of axonal nerve conduction”.