Lateral Antebrachial Cutaneous Nerve as a Donor Source for Digital Nerve Grafting: A Concept Revisited

Clinical anatomy of the lateral antebrachial cutaneous nerve: Is there any safe zone for interventional approach?

INTRODUCTION

The lateral antebrachial cutaneous nerve (LACN) is a somatosensory nerve coursing in the lateral portion of the forearm. The nerve is located in a close proximity to the cephalic vein (CV) all along its course with a danger of being injured during venipuncture. The LACN also overlaps and communicates with the superficial branch of the radial nerve (SBRN) in the distal forearm and hand, making the awareness of their relationship of great importance in the treatment of neuroma. The aim of the study was to observe the relationship of the LACN to surrounding structures as well as its branching pattern and distribution.

MATERIALS AND METHODS

Ninety-three cadaveric forearms embalmed in formaldehyde were dissected. The relationship of the LACN to surrounding structures was noted and photographed, and distances between the structures were measured with a digital caliper. The cross-sectional relationships of the LACN and SBRN to the CV were described using heatmaps.

RESULTS

The emerging point of the LACN was found distally, proximally or at the level of the interepicondylar line (IEL). The LACN branched in 76 cases (81.7 %) into an anterior and posterior branch at mean distance of 47.8 ± 34.2 mm distal to the IEL. The sensory distribution was described according to the relationship of the LACN branches to the medial border of the brachioradialis muscle. The LACN supplying the dorsum of the hand was observed in 39.8 % of cases. The LACN and the SBRN intersected in 86 % of upper limbs with communications noticed in 71 % of forearms. The LACN was stated as the most frequent donor of the communicating branch resulting in neuroma located distal to the communication and being fed from the LACN. The relationship of the LACN and the CV showed that the IEL is the most appropriate place for the venipuncture due to maximal calibers of the CV and deep position of the LACN. The LACN was adjacent to the cubital perforating vein and the radial artery in all cases. The medial border of the brachioradialis muscle was observed less than 1.8 mm from the LACN.

CONCLUSION

The study provides morphological data on the LACN distribution, branching pattern and relationship to surrounding structures in a context of clinical use in different spheres of medicine. The branching pattern of the LACN appears to be more constant compared to data provided by previous authors. We emphasized the meaning of cross-sectional relationship of the LACN to the CV to avoid venipuncture outside the cubital fossa if possible. The posterior branch of the LACN was predicted as appropriate donor of the graft for a digital nerve. The LACN appeared to be in a close proximity within the whole length of the brachioradialis muscle what the orthopedic surgeons must be concerned of. The meaning of the donor-nerve of the communicating branch in neuroma treatment was also introduced.

The Medial Antebrachial Cutaneous Nerve Is a Low-Morbidity Alternative to the Standard Sural Nerve Autograft

BACKGROUND

Nerve interposition grafting is an important technique in nerve reconstructive surgery that is used when a primary repair is not feasible without significant tension. This study sought to evaluate the long-term morbidity of the medial antebrachial cutaneous (MABC) nerve as an alternative donor nerve in comparison with sural nerve harvest.

METHODS

A single surgeon and institution retrospective chart review was performed to identify all patients who underwent nerve autografting using the sural and MABC as donor nerves between January 1, 2000 and December 31, 2019. Surveys assessed overall patient satisfaction with surgery, as well as donor and recipient site morbidity, satisfaction, pain, numbness, and cold sensitivity.

RESULTS

Of the 73 patients contacted, 54 agreed to participate, and 43 of 73 (58.9%) ultimately completed the survey: 28 MABC (65.1%) and 15 sural (34.9%). There were no significant differences between the sural and MABC groups in overall satisfaction with surgery, donor and recipient site satisfaction, pain, cold sensitivity, and effect on quality of life. Even though 66.7% of sural donor sites and 75% of MABC donor sites had residual numbness, the effect this had on quality of life was very low (2 and 3, respectively).

CONCLUSION

The MABC is a safe alternative to the traditional sural nerve autograft. A small subset of patients undergoing nerve autograft harvest will experience long-term morbidity in the form of pain. Conversely, the more common presence of numbness is not reported as bothersome.

Treatment options for digital nerve injury: a systematic review and meta-analysis

BACKGROUND

Surgical treatment of finger nerve injury is common for hand trauma. However, there are various surgical options with different functional outcomes. The aims of this study are to compare the outcomes of various finger nerve surgeries and to identify factors associated with the postsurgical outcomes via a systematic review and meta-analysis.

METHODS

The literature related to digital nerve repairs were retrieved comprehensively by searching the online databases of PubMed from January 1, 1965, to August 31, 2021. Data extraction, assessment of bias risk and the quality evaluation were then performed. Meta-analysis was performed using the postoperative static 2-point discrimination (S2PD) value, moving 2-point discrimination (M2PD) value, and Semmes-Weinstein monofilament testing (SWMF) good rate, modified Highet classification of nerve recovery good rate. Statistical analysis was performed using the R (V.3.6.3) software. The random effects model was used for the analysis. A systematic review was also performed on the other influencing factors especially the type of injury and postoperative complications of digital nerve repair.

RESULTS

Sixty-six studies with 2446 cases were included in this study. The polyglycolic acid conduit group has the best S2PD value (6.71 mm), while the neurorrhaphy group has the best M2PD value (4.91 mm). End-to-side coaptation has the highest modified Highet's scoring (98%), and autologous nerve graft has the highest SWMF (91%). Age, the size of the gap, and the type of injury were factors that may affect recovery. The type of injury has an impact on the postoperative outcome of neurorrhaphy. Complications reported in the studies were mainly neuroma, cold sensitivity, paresthesia, postoperative infection, and pain.

CONCLUSION

Our study demonstrated that the results of surgical treatment of digital nerve injury are generally satisfactory; however, no nerve repair method has absolute advantages. When choosing a surgical approach to repair finger nerve injury, we must comprehensively consider various factors, especially the gap size of the nerve defect, and postoperative complications. Type of study/level of evidence Therapeutic IV.

Repair of complex digital soft‐tissue defects using a free composite ulnar artery perforator flap from the volar wrist

Digital skin defects resulting from trauma are often associated with dysfunction of the digital nerve and the extensor and flexor tendons in the affected fingers. The repair of these complex tissue defects requires a graft containing multiple tissues that can be used to reconstruct the tendons and nerves and restore the skin. Such procedures can cause multiple injuries and significant damage to the donor site. The current study used a novel technique to repair complex dorsal and palmar digital soft-tissue defects. First, multiple tissues were cut and collected from the donor site. Then, part of the flexor carpi ulnaris tendon was transplanted to repair the tendon defect, and a medial antebrachial cutaneous nerve graft was used to repair the digital nerve defect. Finally, a skin flap was used to cover the skin defect. This paper reports on 31 cases of complex soft-tissue digital defects, with defect areas of 2-18 cm² . One patient presented with a postoperative arterial crisis in the flap. All other patients recovered without experiencing a vascular crisis, flap necrosis, or wound infection. The postoperative flaps were similar in texture to the original digital skin. The sensation and the extension/flexion functions in the affected fingers recovered well. The effect on grip strength, wrist flexion, and forearm sensation was minor and the postoperative total active motion scores of the affected digits were good or excellent in 96.77% of the cases. The flap sensation recovery rate was also excellent in 83.87% of the cases. The present technique facilitates the repair of multiple dorsal and palmar digital soft-tissue, tendon and nerve defects, reduces the damage to the donor site, and significantly improves the success of surgical repair.

Vascularization of the lateral and medial antebrachial cutaneous nerves by cutaneous perforator arteries: An anatomical study

The forearm is an interesting donor site for non-vascularized nerve grafts, especially hand surgeons. Very few studies have described the use of the lateral and medial antebrachial cutaneous nerves (LABCN and MABCN, respectively) as vascularized nerve grafts (VNGs). The aim of this anatomical study was to analyze the characteristics and vascularization of these nerves to describe new potential donor sites for VNGs. Twelve forearms were dissected from fresh cadavers injected with red latex. The number of terminal branches, lengths, and proximal and distal diameters of both the LABCN and MABCN were studied. An anatomical description of the cutaneous perforator arteries from the radial and ulnar arteries that vascularized the nerve was also recorded: number of perforators, length, type of perforator (septo- or musculocutaneous), and location within the forearm (proximal, middle, and distal third). In over 80% of the specimens, the cutaneous perforator arteries from the radial and ulnar artery vascularized the LABCN and the MABCN, respectively. These arteries, found mostly in the proximal third of the forearm, had diameters >0.5mm. Most of them came from the radial and ulnar arteries (for LABCN and MABCN vascularization, respectively). In over 75% of the specimens, the nutrient arteries of both nerves also vascularized the superficial veins and the skin. We found that these nerves are vascularized by perforators arteries, which also participate in vein and skin vascularization. Altogether, this anatomical study shows that reconstructive surgeons could use new VNGs based on the perforator artery of the forearm.

Donor nerve graft assessment for covering thumb nerve defects: a cadaveric study

BACKGROUND

Even though several studies reported donor autologous nerve grafts for digital nerve defects, there is no report in the literature regarding acceptable graft for thumb nerves. The purpose of this study is to provide guidelines for autologous nerve graft selection by detecting similarities between thumb nerve zones and donor nerve with regard to the number of fascicles and cross-sectional area.

MATERIALS AND METHODS

Five cadavers were used in this study. An anatomical zoning system was defined for thumb nerves (zones 1, 2, 3). Sural nerve (SN), medial antebrachial cutaneous nerve (MABCN), lateral antebrachial cutaneous nerve (LABCN), posterior interosseous nerve (PIN), and anterior interosseous nerve (AIN) were selected as donor nerve grafts. The number of fascicles and surface area (mm2) was defined.

RESULTS

The mean of the fascicle number in zone 1, zone 2, zone 3, AIN, PIN, LABCN, MABCN, and SN were 3.8, 4.7, 6.1, 2.2, 1.8, 4.5, 3.1, and 6.4, respectively. The mean of the surface area in zone 1, zone 2, zone 3, AIN, PIN, LABCN, MABCN, and SN were 2.19, 6.26, 4.04, 1.58, 0.71, 5.00, 3.01, and 8.06, respectively.

CONCLUSIONS

LABCN is the best choice for all zones that has fascicular matching with all three zones of thumb nerves and caliber matching with zones 2 and 3. In zone 1, the best nerve graft is MABCN which has both suitable caliber and fascicle count.

Cutaneous nerve-conscious surgical repair of vascular access-related aneurysm assisted by anatomical ultrasonography in hemodialysis patients

BACKGROUND

The superficial runoff veins anatomically run alongside the cutaneous nerves in the volar forearm. Consequently, the surgical repair of vascular access (VA)-associated venous aneurysms attached to the cutaneous nerves could cause intraoperative nerve injury. Therefore, we proposed a cutaneous nerve-conscious VA-related aneurysmal repair assisted by nerve ultrasonography. This ultrasonography aids in the preoperative examination of the courses of the nerves neighboring the aneurysm.

METHODS

Sixteen consecutive patients who underwent surgical revisions of VA-related aneurysms (14 venous aneurysms and two arterial pseudoaneurysms) were enrolled. The locations of aneurysms derived from preexisting arteriovenous fistulas included 11 radiocephalic arteriovenous fistulas in the wrist or distally, three radiocephalic arteriovenous fistulas at the antecubital fossa, and two brachiocephalic arteriovenous fistulas at the antecubital fossa or in the distal upper arm. A preoperative ultrasonographic scan of the cutaneous nerve trunks that ran peripherally toward and along the aneurysms was attempted to avoid nerve injuries during operations. Basically, the aneurysms were resected from the proximal to the distal ends after being separated from the preserved adjacent nerves.

RESULTS

The cutaneous nerve trunks that coursed toward and along the aneurysm could be identified by preoperative ultrasonography and could be preserved intraoperatively based on ultrasonographic findings in all patients. In four patients, the cutaneous nerve branch was unexpectedly or intentionally severed for a seamless surgical process because the nerve branch that divided from the cutaneous nerve trunk was strongly attached to the aneurysm. They subsequently suffered from hypoesthesia, but did not experience neuropathic pain.

CONCLUSION

Preoperative ultrasonographic examination of the cutaneous nerve facilitated the intraoperative prevention of cutaneous nerve injury in VA-related aneurysmectomy. Nerve-sparing VA surgery assisted by preoperative nerve ultrasonography based on the understanding of topological anatomy might contribute to the reduction in postoperative neuropathy and enhance comfort in the daily life of hemodialysis patients.