Alternatives to sural nerve grafts in the upper extremity

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.

Vascularized versus Free Nerve Grafts: An Experimental Study on Rats

BACKGROUND

Vascularized nerve grafts (VNGs) have been proposed as a superior alternative to free nerve grafts (FNGs) for complex nerve defects. A greater regenerative potential has been suggested by clinical and experimental studies, but conclusive evidence is still lacking.

METHODS

In this experimental study, 10 adult male Wistar rats received a non-vascularized orthotopic sciatic nerve graft on their right side, and a vascularized orthotopic sciatic nerve graft nerve on their left side. Functional outcome following nerve regeneration was evaluated through electrodiagnostic studies, target muscles weight and histomorphology, and data of VNGs and FNGs were compared.

RESULTS

The results of this study showed a significant difference in the motor unit number of Gastrocnemius Medialis (GM) estimated by MUNE in the VNG side compared to the FNG side. No other significant differences in axonal regeneration and muscle reinnervation were evident at either electrodiagnostic, histomorphology studies or muscle weight.

CONCLUSIONS

This experimental model showed slight differences in nerve regeneration between VNGs and FNGs, but cannot support a high clinical advantage for VNGs. The results of this study show that VNGs are not strongly superior to FNGs in the rat model, even in avascular beds. Clinical advantages of VNGs are likely to be limited to extensive and thick nerve defects and can only be assessed on experimental model with bigger animals. Also, we showed that the MUNE technique provided a reliable and reproducible evaluation of functional outcomes in the rat sciatic nerve and defined a reproducible protocol for functional evaluation of muscle reinnervation.

Long-Term Donor-Site Morbidity Following Entire Sural Nerve Harvest for Grafting

PURPOSE

The sural nerve is the autologous nerve used most commonly for grafting. However, recent studies indicate a high rate of complications and complaints after sural nerve removal. In this prospective study, we evaluated donor-site morbidity following full-length sural nerve harvesting on long-term follow-up.

METHODS

Fifty-one legs from 43 patients who underwent complete sural nerve harvesting for brachial plexus reconstruction were included in the study. After an average of 5 years, with a minimum postoperative follow-up of 12 months, sensory deficits in the leg and foot were analyzed using 2.0-g monofilaments. Regions of sensory deficit were marked with a skin marker and photographed. Over these regions of decreased sensation, we tested nociception using an eyebrow tweezer. Patients were also asked about pain, cold intolerance, pruritis, difficulties walking, and foot swelling.

RESULTS

Regions most affected (84% of patients) were over the calcaneus and cuboid. However, in these regions, nociception was preserved. Regions of decreased sensation extended to the calf region in 11 of 51 legs. In 13 patients, we also observed regions of decreased sensation on the proximal leg. In five feet, the sensation was entirely preserved. No patient had any complaints about pain, cold intolerance, itchiness, difficulties walking, or foot swelling.

CONCLUSION

Decreased sensation with nociception preserved was most common along the lateral side of the foot over the calcaneus and cuboid. Removing the entire sural nerve produced no long-term complaints of pain. Sural nerve use appears safe.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

An Updated Surgical Approach of Using Flap and Cutaneous Nerve in the Lateral Arm to Reconstruct Complex Injuries of the Forearm and Hand: A Case Series Study

BACKGROUND

Complex injuries involving the nerves and other soft tissues in the forearm and hand lead to functional and aesthetic defects. In such situations, multiple types of nerve autografts and flap donor sites are available. However, multiple donor sites cause donor morbidity in different locations and may lead to awkward operational positions. Therefore, based on the anatomical characterization, we aimed to modify the utilization of the lateral arm donor site for reconstruction, which restricts donor morbidity in the affected upper extremity.

METHODS

We report a case series (N = 6) using a lateral arm flap (LAF) to reconstruct complex soft tissue defects in the forearm, palm, and finger. The posterior antebrachial cutaneous nerve (PACN) is the primary option for nerve bridging, whereas the LAF can carry the lower lateral brachial cutaneous nerve (LBCN) as a sensory flap. Once the PACN was insufficient, the LBCN was harvested simultaneously. All the cases included in this study were performed between January 2012 and August 2021. Demographic information, flap and nerve characteristics, complications, and hand function were analyzed.

RESULTS

The LAF plus PACN or plus LBCN as nerve autograft, both successfully repaired 6 complex injuries: 2 cases in the forearm side, 1 in the hand palm, and 3 in the finger defects. Posterior antebrachial cutaneous nerve was the most used (8-15 cm), and LBCN plus PACN was used to bridge nerve defects when necessary (in total, 20 and 21 cm). The average follow-up time was 19.7 months. The disabilities of the arm, shoulder and hand score ranged between 6 and 12, and the mean 2-point discrimination values ranged between 6 and 12. The Semmes-Weinstein monofilament test result was under 5.46. In addition, 2 patients underwent a secondary debulking surgery. The average length of hospital stay was 10.4 days. Hematoma occurred in 2 cases, and all patients reported numbness in the donor nerve innervated areas.

CONCLUSIONS

This surgical refinement can reconstruct complex injuries in the forearm and hand. In addition, this approach restricts donor morbidity in the affected limb, comforts the operational position, and is achieved under brachial plexus anesthesia.

Histologic Comparison of the Fascicular Area of Processed Nerve Allograft Versus Cabled Sural Nerve Autograft

Background

The use of multiple cables of sural nerve autograft is common for peripheral nerve reconstruction when injured nerve caliber exceeds the nerve graft caliber. Although the optimal matching of neural to nonneural elements and its association with functional outcomes are unknown, it is reasonable to consider maximizing the neural tissue structure available for nerve regeneration. No prior studies have compared directly the cross-sectional fascicular area between cabled nerve autografts and size-selected nerve allografts. This study evaluated the cross-sectional fascicular area between native nerve stumps and two reconstructive nerve grafting methods: cabled sural nerve autograft (CSNA) and processed nerve allograft (PNA).

Methods

CSNA from matched cadaveric specimens and PNA were used to reconstruct nerve defects in the median and ulnar nerves of six pairs of cadaveric specimens. Nerve reconstructions were done by fellowship-trained hand surgeons. The total nerve area, fascicular area, and nonfascicular area were measured histologically.

Results

The CSNA grafts had significantly less fascicular area than PNA and caliber-matched native nerve. The PNA grafts had a significantly higher percent fascicular area compared with the intercalary CNSA graft.

Conclusions

Fascicular area was significantly greater in PNA versus CSNA. The PNA consistently demonstrated a match in fascicular area closer to the native nerve stumps than CSNA, where CSNA had significantly smaller fascicular area compared with native nerve stumps.

Acellular Nerve Allografts in Major Peripheral Nerve Repairs: An Analysis of Cases Presenting With Limited Recovery

BACKGROUND

Acellular nerve allografts have been used successfully and with increasing frequency to reconstruct nerve injuries. As their use has been expanded to treat longer gap, larger diameter nerve injuries, some failed cases have been reported. We present the histomorphometry of 5 such cases illustrating these limitations and review the current literature of acellular nerve allografts.

METHODS

Between 2014 and 2019, 5 patients with iatrogenic nerve injuries to the median or ulnar nerve reconstructed with an AxoGen AVANCE nerve allograft at an outside hospital were treated in our center with allograft excision and alternative reconstruction. These patients had no clinical or electrophysiological evidence of recovery, and allograft specimens at the time of surgery were sent for histomorphological examination.

RESULTS

Three patients with a median and 2 with ulnar nerve injury were included. Histology demonstrated myelinated axons present in all proximal native nerve specimens. In 2 cases, axons failed to regenerate into the allograft and in 3 cases, axonal regeneration diminished or terminated within the allograft.

CONCLUSIONS

The reported cases demonstrate the importance of evaluating the length and the function of nerves undergoing acellular nerve allograft repair. In long length, large-diameter nerves, the use of acellular nerve allografts should be carefully considered.

Expectant Management, Tendon Transfer, or Nerve Transfer Surgery for Radial Nerve Injury: A Qualitative Study Exploring Patient Expectations, Goals, and Treatment Experiences

BACKGROUND

After a radial nerve injury, patients must weigh a complicated set of advantages and disadvantages to observation or surgery. We conducted semistructured interviews to characterize the decision-making process that these patients undertake.

METHODS

We recruited participants who were treated with expectant management (nonoperatively), received only a tendon transfer, or received a nerve transfer. Participants completed a semistructured interview that was transcribed and coded to identify recurring themes, to describe the influence of qualitative findings on treatment decision-making.

RESULTS

We interviewed 15 participants (5 expectant management, 5 tendon transfer only, and 5 nerve transfer). Participants' primary concerns were returning to work, hand appearance, regaining motion, resuming activities of daily living, and enjoying hobbies. Delayed diagnosis and/or insurance coverage led 3 participants to change treatment from nerve transfer to isolated tendon transfer. Interactions with providers early in diagnosis and treatment had strong effects on how members of the care team were perceived. The hand therapist was the primary person who shaped expectations, provided encouragement, and prompted referral to the treating surgeon. Participants valued debate among the care team members regarding treatment, provided that medical terminology was explained.

CONCLUSIONS

This study highlights the importance of initial, collaborative care in setting expectations for patients with radial nerve injuries. Many participants named returning to work and hand appearance as primary concerns. Hand therapists were the primary source of support and information during recovery.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Revision of Carpal Tunnel Surgery

Carpal tunnel release is one of the most commonly performed upper extremity procedures. The majority of patients experience significant improvement or resolution of their symptoms. However, a small but important subset of patients will experience the failure of their initial surgery. These patients can be grouped into persistent, recurrent, and new symptom categories. The approach to these patients starts with a thorough clinical examination and is supplemented with electrodiagnostic studies. The step-wise surgical management of revision carpal tunnel surgery consists of the proximal exploration of the median nerve, Guyon’s release with neurolysis, the rerelease of the transverse retinaculum, evaluation of the nerve injury, treatment of secondary sites of compression, and potential ancillary procedures. The approach and management of failed carpal tunnel release are reviewed in this article.

Comparison of Outcomes of Spinal Accessory to Suprascapular Nerve Transfer Versus Nerve Grafting for Neonatal Brachial Plexus Injury

Neonatal brachial plexus injuries may cause critical limitations of upper extremity function. The optimal surgical approach to address neonatal brachial plexus injuries has not been defined. In this systematic review, we compare clinical results after spinal accessory to suprascapular nerve transfer and nerve graft techniques among patients with neonatal brachial plexus injury. [Orthopedics. 2022;45(1):7-12.].

Outcomes of Tibial Nerve Repair and Transfer: A Structured Evidence-Based Systematic Review and Meta-Analysis

Although nerve transfer and repair are well-established for treatment of nerve injury in the upper extremity, there are no established parameters for when or which treatment modalities to utilize for tibial nerve injuries. The objective of our study is to conduct a systematic review of the effectiveness of end-to-end repair, neurolysis, nerve grafting, and nerve transfer in improving motor function after tibial nerve injury. PubMed, Cochrane, Medline, and Embase libraries were queried according to the PRISMA guidelines for articles that present functional outcomes after tibial nerve injury in humans treated with nerve transfer or repair. The final selection included Nineteen studies with 677 patients treated with neurolysis (373), grafting (178), end-to-end repair (90), and nerve transfer (30), from 1985 to 2018. The mean age of all patients was 27.0 ± 10.8 years, with a mean preoperative interval of 7.4 ± 10.5 months, and follow-up period of 82.9 ± 25.4 months. The mean graft repair length for nerve transfer and grafting patients was 10.0 ± 5.8 cm, and the most common donor nerve was the sural nerve. The most common mechanism of injury was gunshot wound, and the mean MRC of all patients was 3.7 ± 0.6. Good outcomes were defined as MRC ≥ 3. End-to-end repair treatment had the greatest number of good outcomes, followed by neurolysis. Patients with preoperative intervals less than 7 months were more likely to have good outcomes than those greater than 7 months. Patients with sport injuries had the highest percentage of good outcomes in contrast to patients with transections and who were in MVAs. We found no statistically significant difference in good outcomes between the use of sural and peroneal donor nerve grafts, nor between age, graft length, and MRC score.

Bifurcation of the sciatic nerve: A descriptive study on a South African cadaver cohort

BACKGROUND

The sciatic nerve bifurcates into the tibial and common fibular nerves in six different regions: the pelvic region, gluteal region, proximal, middle, or distal third of the posterior thigh, or in the popliteal fossa. Inadequate knowledge of sciatic nerve anatomy could lead to failed nerve blocks, and damage during intramuscular injections. Limited studies have been done on African population groups and lack a quantifiable method to classify the levels of sciatic nerve bifurcation.

AIM

Thus, this descriptive cadaver study aimed to assess the bifurcation level of the sciatic nerve in a South African population group using a quantifiable method.

METHODS

Three hundred and thirty-eight formalin-fixed limbs from three universities were dissected between March and August 2018. Type A was classified if the sciatic nerve bifurcated within the pelvic region. A sciatic nerve bifurcation level index (SNBLI) was developed for this study to quantitatively classify the region of sciatic nerve bifurcation into types B to F.

RESULTS

Type F bifurcation was most common (79.6%), and types B and C were not observed. In 15 (0.04%) specimens, two separate nerves entered the gluteal region and converged to form the sciatic nerve distal to the piriformis, which could bifurcate either in the distal third of the posterior thigh or popliteal fossa.

CONCLUSION

This is the first study to provide information on the sciatic nerve bifurcation in a large South African cadaver cohort. Moreover, we created a quantifiable method that can be used to classify the sciatic nerve bifurcation level. This will be beneficial in ensuring accurate comparison between different population groups in future.

Posterior Interosseous Nerve Graft: Utilizing External Landmarks and Anthropometric Ratios to Predict Available Length for Digital Nerve Reconstruction in a Cadaveric Study

Objective:

In digital nerve defects that require grafting, autografts remain the efficacious option. The sensory posterior interosseous nerve (PIN) is an ideal choice as it is of similar caliber to digital nerves and leaves no donor morbidity upon resection. However, a finite length of harvestable PIN exists, and considerable variations of this length have been reported in the literature. There exists no predictive model to estimate this length. We sought to determine a method to accurately predict the available length of PIN based on individual patient anthropometry.

Methods:

A cadaveric dissection study was performed in a fresh tissue laboratory. The length of the sensory branch of the PIN and various anthropometric measurements were made in respect to surface anatomy of the ulna to develop a predictable ratio for available PIN donor graft.

Results:

A total of 16 specimens were obtained. On average the length of the PIN was 5.7 cm (range: 3.3-9. cm) and the length of the ulna was 25.7 cm (range: 23.5-30.6 cm). The ratio of PIN to ulnar length was 0.222 ( r = 0.4651). Using one-fifth the length of the ulna, the mean predicted length of the PIN was 5.14 cm (range: 4.7-6.1 cm). On univariate analysis, there was no significant difference between the measured and predicted PIN length ( P = .249).

Conclusion:

An anthropometric ratio predicated on reproducible surface anatomy of the ulna is a useful tool in predicting the sensory PIN length. Such a prediction may be a useful in guiding patient discussions concerning surgical options for digital nerve reconstruction.

Anatomy of the sural nerve complex: Unaccounted anatomic variations and morphometric data

BACKGROUND

The sural nerve (SN) is a cutaneous sensory nerve innervating the posterolateral leg. The SN is formed from a highly variable set of contributing nerves called the sural nerve complex (SNC). The SNC is made up of the lateral sural cutaneous nerve, medial sural cutaneous nerve, sural communicating branch, and SN. The SN is frequently cited as the most common donor nerve graft and is commonly injured in procedures of the lower extremity. Recent meta-analysis standardized six morphologies of the SNC and established a required reporting criterion for the group of nerves forming the SN. Due to the inconsistencies in previous literature, this study will group observed SNC's by one of these six SNC morphologies to assess and validate the meta-analysis grouping criteria. This study will also collect the same morphometric data previously outlined in order to grow the number of samples that are reported in a standardized fashion.

METHODS

100 formalin and 4 Theil preserved cadavers (n = 208) lower limbs were bilaterally dissected at Kansas City University and Creighton University School of Dentistry to observe the SNC in its entirety on the posterolateral leg. Anatomic data was captured utilizing the standardized morphologies types 1-6 with two sub-typing. Nerves that were found to be outside of this categorization were placed in an unassigned grouping.

RESULTS

The most prevalent SNCs were type 1 at 41.35% (n = 86) and type 3 nerves at 34.62% (n = 72). Type 2 was found 8.65% (n = 18), type 4 and 5 were found each at 0.48% (n = 1). Type 6 was not observed. When comparing the present studies frequency of nerve types 1-6 to the meta-analysis a sub-grouping of "North American" cadaveric studies a X² = .903 p = .030 was found. Two distinct and previously unassigned formations of the SNC were 10.58% (n = 20) and 3.85% (n = 8) of data. These two SNC are termed type 7 & 8, these represent two formations of SN that are outside of what was previously reported. 15.87% (n = 33) did not match visual descriptions based on nerve origin of a type 1 SNC but met written definitions. These were termed type 1A1 and type 1A2. The SNC was asymmetrical in 57.69% (n = 120). The pooled mean length of the SN was 32.97 ± 14.12 cm (31.05-34.88), mean diameter was 2.31 ± 0.83 mm (2.20-2.42, and the distance of the posterior border of the lateral malleolus to the SN was found to be 1.72 ± 0.70 cm (1.63-1.80).

CONCLUSION

Anatomic variation in the SNC is highly variable, yet is consistent with previously observed literature. This study demonstrates two unaccounted formations of the SNC as well as two additional subcategories of SNC that were not included in the previous meta-analysis. These four variants warrant inclusion as standard formations of the SNC due to the high prevalence observed in this study as well as historical consistency observed in previous literature and case reports. These two SNC formations increase the risk of iatrogenic injury during surgical interventions of the lower extremity. Morphometric data describing the spatial relationship of this nerve complex on the posterolateral leg is consistent with previously reported data and aids in generating a large data set for future studies to characterize spatial properties of this nerve complex.

Current concepts in diagnosis and management of common upper limb nerve injuries in children

Peripheral nerve injuries (PNI) of the upper limb are a common event in the paediatric population, following both fractures and soft tissues injuries. Open injuries should in theory be easier to identify and the repair of injured structures performed as soon as possible in order to obtain a satisfying outcome. Conversely, due to the reduced compliance of younger children during clinical assessment, the diagnosis of a closed nerve injury may sometimes be delayed. As the compliance of patients is influenced by pain, anxiety and stress, the execution of the clinical manoeuvres intended to identify a loss of motor function or sensibility, can be impaired. Although the majority of PNI are neuroapraxias resulting in spontaneous recovery, there are open questions regarding certain aspects of closed PNI, e.g. when to ask for electrophysiological exams, when and how long to wait for a spontaneous recovery and when a surgical approach becomes mandatory. The aim of the article is therefore to analyse the main aspects of the different closed PNI of the upper limb in order to provide recommendations for timely and correct management, and to determine differences in the PNI treatment between children and adults.

Three-Dimensional Engineered Peripheral Nerve: Toward a New Era of Patient-Specific Nerve Repair Solutions

Reconstruction of peripheral nerve injuries (PNIs) with substance loss remains challenging because of limited treatment solutions and unsatisfactory patient outcomes. Currently, nerve autografting is the first-line management choice for bridging critical-sized nerve defects. The procedure, however, is often complicated by donor site morbidity and paucity of nerve tissue, raising a quest for better alternatives. The application of other treatment surrogates, such as nerve guides, remains questionable, and it is inefficient in irreducible nerve gaps. More importantly, these strategies lack customization for personalized patient therapy, which is a significant drawback of these nerve repair options. This negatively impacts the fascicle-to-fascicle regeneration process, critical to restoring the physiological axonal pathway of the disrupted nerve. Recently, the use of additive manufacturing (AM) technologies has offered major advancements to the bioengineering solutions for PNI therapy. These techniques aim at reinstating the native nerve fascicle pathway using biomimetic approaches, thereby augmenting end-organ innervation. AM-based approaches, such as three-dimensional (3D) bioprinting, are capable of biofabricating 3D-engineered nerve graft scaffolds in a patient-specific manner with high precision. Moreover, realistic in vitro models of peripheral nerve tissues that represent the physiologically and functionally relevant environment of human organs could also be developed. However, the technology is still nascent and faces major translational hurdles. In this review, we spotlighted the clinical burden of PNIs and most up-to-date treatment to address nerve gaps. Next, a summarized illustration of the nerve ultrastructure that guides research solutions is discussed. This is followed by a contrast of the existing bioengineering strategies used to repair peripheral nerve discontinuities. In addition, we elaborated on the most recent advances in 3D printing and biofabrication applications in peripheral nerve modeling and engineering. Finally, the major challenges that limit the evolution of the field along with their possible solutions are also critically analyzed.

Fibular Nerve Repair by Lateral Sural Cutaneous Nerve Graft: Anatomic Feasibility Study and Clinical Results

OBJECTIVE

The common fibular nerve (CFN) is the most frequently injured nerve in the lower limbs. Surgical management is necessary in approximately two thirds of patients and includes neurolysis, suture, graft repair, or nerve transfer. The distal sural nerve is the preferred donor for grafting, but it is not without complications and requires a second incision. We sought to study the surgical anatomy of the lateral sural cutaneous nerve (LSCN) with the aim of repairing CFN injuries through the same incision and as a potential source for grafting in other nerve injuries.

METHODS

The popliteal fossa was dissected in 11 lower limbs of embalmed cadavers to study LSCN variations. Four patients with CFN injuries then underwent surgical repair by LSCN grafting using the same surgical approach.

RESULTS

At the medial margin of the biceps femoris, the LSCN emerged from the CFN approximately 8.15 cm above the fibular head. The LSCN ran longitudinally to the long axis of the popliteal fossa, with an average of 3.2 cm medial to the fibular head. The mean LSCN length and diameter were 9.61 cm and 3.6 mm, respectively. The LSCN could be harvested in all patients for grafting. The mean graft length was 4.4 cm. Motor function was consistently recovered for foot eversion but was recovered to a lesser extent for dorsiflexion and toe extension. All patients recovered sensitive function (75% of S3). Hypoesthesia was recognized at the calf.

CONCLUSIONS

LSCN harvest is a viable alternative for nerve grafting, especially for repairing short CFN injuries, thereby avoiding the need for a second incision.

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.

Arm reconstruction

The arm is less often concerned by reconstructive surgeries than more distal parts of the upper extremity. However, when affected, the arm is frequently part of complex mutilating injuries involving composite defects. For a given traumatic or oncologic defect, there are several reconstructive options and choosing the right sequence may pose a challenge even to the most experienced surgeon. The latter must integrate not only functional and esthetic requirements, but also the surgeon's habits, especially in situations of emergency. Once life-threatening conditions are averted, wound debridement, bony stabilization, neurovascular, and cutaneous reconstruction tailored to the defects should be performed in a single-stage procedure. Functionally, prompt bony stabilization is necessary to allow early mobilization. Diaphyseal shortening of the humerus can be a salvage procedure to avoid nerve and vascular grafting, with good biomechanical tolerance up to 5cm. Restoration of adequate elbow motion sometimes requires muscle transfer and should be a main concern, as proper positioning of the hand during daily activities demands a functional elbow joint. Esthetically, the surgeon must choose the most cosmetic skin coverage option whilst limiting morbidity of the donor site area. The flaps vascularized by the sub- scapular or thoraco-dorsal vessels are the most useful flaps for arm reconstruction. This paper discusses the reconstructive sequence of complex defects of the arm and provides a review of commonly used reconstructive techniques supported with illustrative cases.

An Anatomical Feasibility Study Using a Great Auricular Nerve Graft for Ipsilateral Inferior Alveolar Nerve Repair

The great auricular nerve (GAN) has been used for trigeminal and facial nerve repair and the inferior alveolar nerve (IAN) are often sacrificed during segmental mandibulectomy. To our knowledge, only 1 case report has discussed IAN repair using GAN after segmental mandibulectomy. The goal of this study is to clarify the feasibility of using GAN for IAN repair. Eleven sides from 6 fresh frozen Caucasian cadavers were used for this study. The mean age at the time of death was 82.3 years. A submandibular skin incision was made 2 finger breadths below and parallel to the inferior border of the mandible. The GAN was identified and then the mental foramen was found via extraoral dissection. The buccal cortical bone was removed 5 mm posterior to the mental foramen to the wisdom tooth area. Next, the anteroposterior length of the window was measured. The diameter of the IAN at the first molar tooth area was measured. Finally, the GAN was cut with maximum available length to compare to the length of the window in the mandible. The anteroposterior length of the window and diameter of the IAN ranged from 23.1 to 31.2 mm and 1.2 to 2.1 mm, respectively. The length of the available GAN was longer than the ipsilateral bony window of the mandible on all sides. This study might encourage surgeons to consider a new way to treat patients who undergo segmental resection of the mandible with surgical neck dissection with injury to their IAN.

The Surgical Management of Nerve Gaps: Present and Future

Peripheral nerve injuries can result in significant morbidity, including motor and/or sensory loss, which can affect significantly the life of the patient. Nowadays, the gold standard for the treatment of nerve section is end-to-end neurorrhaphy. Unfortunately, in some cases, there is segmental loss of the nerve trunk. Nerve mobilization allows primary repair of the sectioned nerve by end-to-end neurorrhaphy if the gap is less than 1 cm. When the nerve gap exceeds 1 cm, autologous nerve grafting is the gold standard of treatment. To overcome the limited availability and the donor site morbidity, other techniques have been used: vascularized nerve grafts, cellular and acellular allografts, nerve conduits, nerve transfers, and end-to-side neurorrhaphy. The purpose of this review is to present an overview of the literature on the applications of these techniques in peripheral nerve repair. Furthermore, preoperative evaluation, timing of repair, and future perspectives are also discussed.

Collagen Nerve Conduits and Processed Nerve Allografts for the Reconstruction of Digital Nerve Gaps: A Single-Institution Case Series and Review of the Literature

OBJECTIVE

A single-institution case series is reported and a review of the literature on the outcomes of digital nerve gap reconstruction with the NeuraGen type 1 collagen nerve conduit (Integra Life Sciences, Plainsboro New Jersey, USA) and the Avance Nerve Graft (Axogen Inc., Alachua, Florida, USA) is presented.

METHODS

Thirty-seven patients were included with a minimal follow-up of 12 months. Primary outcome was postoperative sensory recovery measured by static 2-point discrimination test or the Semmes-Weinstein monofilament test. Secondary outcome measurements were perioperative or postoperative complications. Final outcome data were stratified to grade results as excellent, good, or poor.

RESULTS

The mean nerve gap length was 14 ± 4.9 mm for the collagen conduits versus 18.4 ± 9.3 for nerve allografts. After 12 months, outcomes were graded as excellent sensory recovery in 48% of the collagen conduit repairs and 39% of the nerve allografts (P = 0.608), good in 26% of the conduits and 55% of the allografts (P = 0.074), and poor in 26% of the conduits versus 6% of the allografts (P = 0.091). One neuroma and 1 infection were reported. Graft rejection or extrusion was not observed.

CONCLUSIONS

Nerve conduits and processed nerve allografts offer convenient off-the-shelf options for digital nerve gap repair. Both techniques offer effective means of reconstructing a digital nerve gap <2.5 cm at a minimum of 12 months of follow-up. Future prospective randomized large sample size studies comparing nerve conduits with allografts are needed to perform subgroup analyses and to define their exact role in digital nerve injuries.

The Role of the Peripheral Nerve Surgeon in the Treatment of Pain

Pain is a frequent cause of physician visits. Many physicians find these patients challenging because they often have complicated histories, emotional comorbidities, confusing examinations, difficult problems to fix, and the possibility of factitious complaints for attention or narcotic pain medications. As a result, many patients are lumped into the category of chronic, centralized pain and relegated to pain management. However, recent literature suggests that surgical management of carefully diagnosed generators of pain can greatly reduce patients' pain and narcotic requirements. This article reviews recent literature on surgical management of pain and four specific sources of chronic pain amenable to surgical treatment: painful neuroma, nerve compression, myofascial/musculoskeletal pain, and complex regional pain syndrome type II.

Systematic Review of Tendon Transfer Versus Nerve Transfer for the Restoration of Wrist Extension in Isolated Traumatic Radial Nerve Palsy

Purpose:

To compare the outcomes of tendon transfer and nerve transfer for radial nerve palsy.

Methods:

We performed a systematic review of the literature in EMBASE, PubMed, and Cochrane Database to include studies that address persistent traumatic radial nerve palsy treated with tendon transfer or nerve transfer surgery.

Results:

We identified 2,044 citations; 1,512 texts were excluded because of content, and 96 texts were screened for eligibility. Texts were excluded if they did not report the motor score (M0 to M5 as determined by the British Medical Research Council) or measurements of range of motion of the wrist. Sixteen texts were eligible for qualitative synthesis. Outcomes of these studies show heterogeneity with regard to the technique and functional restoration.

Conclusions:

On the basis of the results of this systematic review, there does not seem to be a clearly superior technique; rather, there are advantages and disadvantages to each. Patient selection and surgeon experience are important when considering surgical interventions in this challenging clinical scenario. Nerve transfer surgery is an emerging technique that may offer patients meaningful functional gains with reduced donor site morbidity.

Level of Evidence:

Level III

Radial nerve palsy

As a result of its proximity to the humeral shaft, as well as its long and tortuous course, the radial nerve is the most frequently injured major nerve in the upper limb, with its close proximity to the bone making it vulnerable when fractures occur.Injury is most frequently sustained during humeral fracture and gunshot injuries, but iatrogenic injuries are not unusual following surgical treatment of various other pathologies.Treatment is usually non-operative, but surgery is sometimes necessary, using a variety of often imaginative procedures. Because radial nerve injuries are the least debilitating of the upper limb nerve injuries, results are usually satisfactory.Conservative treatment certainly has a role, and one of the most important aspects of this treatment is to maintain a full passive range of motion in all the affected joints.Surgical treatment is indicated in cases when nerve transection is obvious, as in open injuries or when there is no clinical improvement after a period of conservative treatment. Different techniques are used including direct suture or nerve grafting, vascularised nerve grafts, direct nerve transfer, tendon transfer, functional muscle transfer or the promising, newer treatment of biological therapy. Cite this article: Bumbasirevic M, Palibrk T, Lesic A, Atkinson HDE. Radial nerve palsy. EFORT Open Rev 2016;1:286-294. DOI: 10.1302/2058-5241.1.000028.

Intraneural Median Nerve Anatomy and Implications for Treating Mixed Median Nerve Injury in the Hand

Background: Nerve transfers have resulted in increased interest in the microanatomy of peripheral nerves. Herein, we expand our understanding of the internal anatomy of the digital nerve to the ulnar index and long fingers, the radial long and ring fingers, and the nerves to the second and third web spaces. Methods: The median nerve was dissected from the digital nerves to the antecubital fossa in 14 fresh upper extremities. The distance of proximal internal neurolysis of the fascicles to the second and third web space and proper digital nerves was measured relative to the radial styloid. Plexi encountered during proximal lysis were noted. Results: Digital nerves to the ulnar index and radial long fingers were lysed 2.4 ± 0.5 cm (mean ± SD), and digital nerves to the ulnar long and the radial ring fingers were lysed 3.0 ± 0.6 cm distal to the radial styloid. Fascicles to the third web space were lysed to the takeoff of the anterior interosseous nerve, 21.1 ± 1.4 cm. Plexus groupings were encountered at 4.5 ± 1.6 cm, 8.3 ± 1.2, cm and 16.1 ± 1.9 cm proximal to radial styloid. The fascicles to the second web space were lysed to 5.0 ± 1.2 cm proximal to radial styloid where a plexus grouping was encountered. Another plexus group was found at 3.3 ± 1.3 cm. Conclusions: We demonstrate that extended internal neurolysis of second web space, along with the digital nerves, is technically and clinically feasible. This technique can be used to treat mixed median nerve injury in the hand and wrist.

Ulnar neuropathy: evaluation and management

Ulnar neuropathy is commonly encountered, both acutely after elbow trauma and in the setting of chronic compression neuropathy. Careful clinical evaluation and discerning evaluation of electrodiagnostic studies are helpful in determining the prognosis of recovery with nonoperative and operative management. Appreciation of the subtleties in clinical presentation and thoughtful consideration of the timing and type of surgical intervention are critical to optimizing outcomes after treatment of ulnar neuropathy. The potential need for decompression at both the cubital tunnel and Guyon's canal must be appreciated. Supplementation of decompression with supercharged end-to-side nerve transfer can expedite motor recovery of the ulnar intrinsic muscles in the appropriately selected patient. The emergence of nerve transfer techniques has also changed the management of acute ulnar nerve injuries.

Donor Distal, Recipient Proximal and Other Personal Perspectives on Nerve Transfers

This article presents a personal overview of nerve transfers and emphasizes the various factors that contribute to outcome following these surgeries. There is no "one result" for all nerve transfers. The results will vary depending on factors relating to the donor nerve and the recipient nerve, the degree of the surgical difficulty of the specific procedure, and issues relating to preoperative and postoperative rehabilitation. The general issues that influence all nerve injury and recovery, such as age of the patient, comorbidities, and time since injury, pertain to nerve transfers as well.