Fibrin Glue Coating Limits Scar Tissue Formation around Peripheral Nerves.

Scar tissue formation presents a significant barrier to peripheral nerve recovery in clinical practice. While different experimental methods have been described, there is no clinically available gold standard for its prevention. This study aims to determine the potential of fibrin glue (FG) to limit scarring around peripheral nerves. Thirty rats were divided into three groups: glutaraldehyde-induced sciatic nerve injury treated with FG (GA + FG), sciatic nerve injury with no treatment (GA), and no sciatic nerve injury (Sham). Neural regeneration was assessed with weekly measurements of the visual static sciatic index as a parameter for sciatic nerve function across a 12-week period. After 12 weeks, qualitative and quantitative histological analysis of scar tissue formation was performed. Furthermore, histomorphometric analysis and wet muscle weight analysis were performed after the postoperative observation period. The GA + FG group showed a faster functional recovery (6 versus 9 weeks) compared to the GA group. The FG-treated group showed significantly lower perineural scar tissue formation and significantly higher fiber density, myelin thickness, axon thickness, and myelinated fiber thickness than the GA group. A significantly higher wet muscle weight ratio of the tibialis anterior muscle was found in the GA + FG group compared to the GA group. Our results suggest that applying FG to injured nerves is a promising scar tissue prevention strategy associated with improved regeneration both at the microscopic and at the functional level. Our results can serve as a platform for innovation in the field of perineural regeneration with immense clinical potential.

Incidence of phrenic nerve injury during pulmonary vein isolation using different cryoballoons: data from a large prospective ablation registry.

AIMS: Phrenic nerve injury (PNI) is the most common complication during cryoballoon ablation. Currently, two cryoballoon systems are available, yet the difference is unclear. We sought to compare the acute procedural efficacy and safety of the two cryoballoons. METHODS: This prospective observational study consisted of 2,555 consecutive atrial fibrillation (AF) patients undergoing pulmonary vein isolation (PVI) using either conventional (Arctic Front Advance) (AFA-CB) or novel cryoballoons (POLARx) (POLARx-CB) at 19 centers between January 2022 and October 2023. RESULTS: Among 2,555 patients (68.8 ± 10.9 years, 1,740 men, paroxysmal AF[PAF] 1,670 patients), PVIs were performed by the AFA-CB and POLARx-CB in 1,358 and 1,197 patients, respectively. Touch-up ablation was required in 299(11.7%) patients. The touch-up rate was significantly lower for POLARx-CB than AFA-CB (9.5% vs. 13.6%, p = 0.002), especially for right inferior PVs (RIPVs). The touch-up rate was significantly lower for PAF than non-PAF (8.8% vs. 17.2%, P < 0.001) and was similar between the two cryoballoons in non-PAF patients. Right PNI occurred in 64(2.5%) patients and 22(0.9%) were symptomatic. It occurred during the right superior PV (RSPV) ablation in 39(1.5%) patients. The incidence was significantly higher for POLARx-CB than AFA-CB (3.8% vs. 1.3%, P < 0.001) as was the incidence of symptomatic PNI (1.7% vs. 0.1%, P < 0.001). The difference was significant during RSPV (2.5% vs. 0.7%, P < 0.001) but not RIPV ablation. The PNI recovered more quickly for the AFA-CB than POLARx-CB. CONCLUSIONS: Our study demonstrated a significantly higher incidence of right PNI and lower touch-up rate for the POLARx-CB than AFA-CB in the real-world clinical practice.

Risk of suprascapular nerve injury in open Trillat procedure: an anatomical study.

PURPOSE: The open Trillat Procedure described to treat recurrent shoulder instability, has a renewed interest with the advent of arthroscopy. The suprascapular nerve (SSN) is theoretically at risk during the drilling of the scapula near the spinoglenoid notch. The purpose of this study was to assess the relationship between the screw securing the coracoid transfer and the SSN during open Trillat Procedure and define a safe zone for the SSN. METHODS: In this anatomical study, an open Trillat Procedure was performed on ten shoulders specimens. The coracoid was fixed by a screw after partial osteotomy and antero-posterior drilling of the scapular neck. The SSN was dissected with identification of the screw. We measured the distances SSN-screw (distance 1) and SSN-glenoid rim (distance 2). In axial plane, we measured the angles between the glenoid plane and the screw (α angle) and between the glenoid plane and the SSN (ß angle). RESULTS: The mean distance SSN-screw was 8.8 mm +/-5.4 (0-15). Mean α angle was 11°+/-2.4 (8-15). Mean ß angle was 22°+/-6.7 (12-30). No macroscopic lesion of the SSN was recorded but in 20% (2 cases), the screw was in contact with the nerve. In both cases, the ß angle was measured at 12°. CONCLUSION: During the open Trillat Procedure, the SSN can be injured due to its anatomical location. Placement of the screw should be within 10° of the glenoid plane to minimize the risk of SSN injury and could require the use of a specific guide or arthroscopic-assisted surgery.

Does prophylactic decompression of distal nerves following nerve repair improve functional recovery? A systematic review.

BACKGROUND: Peripheral nerve injuries are burdensome on healthcare systems, individuals and society as a whole. The current standard of treatment for neurotmesis is primary neurorrhaphy or nerve grafting. However, several patients do not recover their full function. There has been a suggestion that primary distal neurolysis at common entrapment sites maximises surgical outcomes; however, no guidelines exist on this practice. This scoping review aims to ascertain the existing evidence on prophylactic distal decompression of peripheral nerves following repair. METHODS: A literature search was performed using Ovid Medline, PubMed, Embase and Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews for studies published in the past 50 years. Studies were screened using a selection criteria and study quality was assessed using standardised tools. Furthermore, thematic content analysis was performed. RESULTS: Six studies were eligible for inclusion after screening; all studies were retrospective and at most level 3 evidence. No studies were designed specifically to assess the efficacy of distal neurolysis following proximal repair, thus no comparative data with control cohorts are available. All studies that recommended distal decompression of proximally repaired nerves based their conclusions on cases observed by the authors in practice or from theories on nerve regeneration. CONCLUSIONS: This systematic review suggests that the evidence on the role of immediate distal neurolysis in primary neurorrhaphy is inadequate. Recommendations are limited by the lack of large-scale and generalisable data. Further research is needed with definitive objective outcomes and patient-related outcome measures.

Can phrenic nerve injury be anticipated by larger cryoballoons?

Recently, a novel size-adjustable cryoballoon has been introduced in clinical practice, which can be inflated to two different diameters (28 and 31 mm). The 31 mm cryoballoon is specifically designed to achieve better contact with remodeled pulmonary veins (PVs) that have wider ostia while avoiding deep cannulation, thereby potentially reducing the risk of phrenic nerve injury (PNI) associated with deep balloon cannulation. However, we encountered two cases of PNI during cryoballoon ablation using the novel system among our initial 25 consecutive case series. Herein, we present two cases that exhibited PNI during freezing of the right superior PV with a size-adjustable balloon. While larger balloons are expected to create a larger area of isolation, the safety of this novel balloon system needs to be evaluated in a large-scale clinical study.

Internal rotation of the shoulder in the beach chair position may increase the risk of iatrogenic suprascapular nerve injury at the spinoglenoid notch during surgical treatment for shoulder instability.

PURPOSE: Suprascapular nerve (SN) at the spinoglenoid notch is a mobile structure which is vulnerable to iatrogenic injury from screw or guidewire penetration during shoulder surgery such as Latarjet procedure or SLAP/Bankart repairs. The primary objective is to identify the distance between posterior glenoid and SN in different shoulder abduction and rotation. The secondary objective is to identify the distance in standard lateral decubitus position. METHODS: Nineteen shoulders from 10 Thiel embalmed soft cadavers were used in this study. The dissection of posterior shoulder was done to identify the SN at spinoglenoid notch. The distance between the posterior glenoid rim and the SN was measured. In beach chair position, the SN distance from six combinations of shoulder position was obtained: adduction/90° internal rotation (ADIR), adduction/neutral rotation (ADN), adduction/90° external rotation (ADER), 45° abduction/90° internal rotation (ABIR), 45° abduction/neutral rotation (ABN), 45° abduction/90° external rotation (ABER). Subsequently, the suprascapular nerve distance was measured in standard lateral decubitus position with 10 lbs. longitudinal traction. RESULTS: In the beach chair position with the shoulder in adduction, the mean distances between the glenoid and the SN in ADIR, ADN and ADER were 15.0 ± 3.3, 19.3 ± 2.6 and 19.5 ± 3.1 mm, respectively. During shoulder abduction, the mean distances when the shoulder was in ABIR, ABN and ABER were 15.2 ± 3.4, 19.4 ± 3.0 and 19.3 ± 2.6 mm, respectively. The mean distance for the lateral decubitus position was 19.3 ± 2.4 mm. The distance between the glenoid and SN was significantly shorter when the shoulder was positioned in internal rotation than in neutral (p < 0.001) or external rotation (p < 0.001) when compared to the same shoulder abduction position. The lateral decubitus position had comparable SN distance with the shoulder position of abduction/neutral rotation in beach chair position. CONCLUSION: The SN was closest to posterior glenoid rim if the shoulder was in internal rotation. Therefore, shoulder internal rotation must be avoided during guidewire and cannulated screw placement in the Latarjet procedure and drill bit insertion during anchor placement in SLAP/Bankart repair.

The use of medial support screw was associated with axillary nerve injury after plate fixation of proximal humeral fracture using minimal invasive deltoid-splitting approach.

BACKGROUND: The purpose of this study was to evaluate the incidence and risk factors for axillary nerve injury after plate fixation of humeral fractures using minimal invasive deltoid-splitting approach. We hypothesized that the use of medial support screw (MSS) would be associated with the outcome of axillary nerve injury. METHODS: This study retrospectively evaluated consecutive 32 patients who underwent surgical treatments for proximal or midshaft humeral fractures. Of them, we included 26 patients who were examined by electromyography/nerve conduction (EMG/NCV) study at 3-4 weeks postoperatively. We excluded 6 patients because two of them were not compliant to EMG/NCV and the remaining two died due to unrelated medical illness. Outcome assessments included pain, functional scores, range of motion, and radiographic results. RESULTS: There were 8 male and 18 female patients with mean age of 67 ± 15 years. Mean duration of follow-up period was 31 ± 11 months. The mean time to EMG/NCS after surgery was 3.5 ± 0.6 weeks. EMG/NCS examinations revealed incomplete axillary nerve injury in 8 patients (31%) without complete nerve injury. Active forward elevation at 3 months postoperatively was significantly lower in patients with axillary nerve injury than in those without it (99° ± 12 and 123° ± 37, respectively, p = 0.047), although final clinical outcomes were not different. At surgery, MSS was used in 17 patients (65%), and 8 of them were associated with nerve injury. The use of MSS was only correlated with the outcome of axillary nerve injury, because the axillary nerve injury developed only in MSS group (p = 0.047). The MMT grade 4 in abduction strength was more common in patients with axillary nerve injury than in those without (p = 0.037). CONCLUSIONS: Axillary nerve injury was a concern after plate fixation of proximal humeral fracture using minimal invasive deltoid-splitting approach. The use of medial support screw to improve the stability could increase a risk of axillary nerve injury when used with this approach.

Intraoperative monitoring of the femoral nerve using free electromyography during total hip arthroplasty via the direct anterior approach.

AIMS: This study aimed to use intraoperative free electromyography to examine how the placement of a retractor at different positions along the anterior acetabular wall may affect the femoral nerve during total hip arthroplasty (THA) when undertaken using the direct anterior approach (THA-DAA). METHODS: Intraoperative free electromyography was performed during primary THA-DAA in 82 patients (94 hips). The highest position of the anterior acetabular wall was defined as the "12 o'clock" position (middle position) when the patient was in supine position. After exposure of the acetabulum, a retractor was sequentially placed at the ten, 11, 12, one, and two o'clock positions (right hip; from superior to inferior positions). Action potentials in the femoral nerve were monitored with each placement, and the incidence of positive reactions (defined as explosive, frequent, or continuous action potentials, indicating that the nerve was being compressed) were recorded as the primary outcome. Secondary outcomes included the incidence of positive reactions caused by removing the femoral head, and by placing a retractor during femoral exposure; and the incidence of femoral nerve palsy, as detected using manual testing of the strength of the quadriceps muscle. RESULTS: Positive reactions were significantly less frequent when the retractor was placed at the ten (15/94; 16.0%), 11 (12/94; 12.8%), or 12 o'clock positions (19/94; 20.2%), than at the one (37/94; 39.4%) or two o'clock positions (39/94; 41.5%) (p < 0.050). Positive reactions also occurred when the femoral head was removed (28/94; 29.8%), and when a retractor was placed around the proximal femur (34/94; 36.2%) or medial femur (27/94; 28.7%) during femoral exposure. After surgery, no patient had reduced strength in the quadriceps muscle. CONCLUSION: Placing the anterior acetabular retractor at the one or two o'clock positions (right hip; inferior positions) during THA-DAA can increase the rate of electromyographic signal changes in the femoral nerve. Thus, placing a retractor in these positions may increased the risk of the development of a femoral nerve palsy. Cite this article: Bone Joint J 2022;104-B(2):193-199.

Impact of mpMRI targeted biopsy on intraoperative nerve-sparing (NeuroSAFE) during robot-assisted laparoscopic radical prostatectomy.

BACKGROUND: The aim of our study was to evaluate the impact of prostate biopsy technique (transrectal ultrasound (US)-prostate biopsy (PBx) versus multiparametric magnetic resonance imaging (mpMRI) targeted prostate biopsy (MRI-PBx) on intraoperative nerve-sparing and the rate of secondary neurovascular-bundle resection (SNR) in patients undergoing robot-assisted laparoscopic radical prostatectomy (RARP). A real-time investigation with a frozen-section examination (NeuroSAFE) microscopically excluded or confirmed prostate cancer invasion of the nerve structures resulting in preservation of the neurovascular bundle or SNR. Additionally, we analyzed risk factors related to SNR, such as longer operation time and postoperative complications. METHODS: The total study cohort was stratified according to non-nerve-sparing versus nerve-sparing RARP. Patients with nerve-sparing approach were then stratified according to biopsy technique (PBx vs. MRI-PBx). Further, we compared PBx versus MRI-PBx according to SNR rate. RESULTS: We included a total of 470 consecutive patients, who underwent RARP for PCa at our institution between January 2016 and December 2019. Patients with a preoperative MRI-PBx had a 2.12-fold higher chance of successful nerve-sparing (without SNR) compared to patients with PBx (p < 0.01). Patients with preoperative MRI-PBx required 73% less intraoperative SNR compared to patients with PBx (p < 0.0001). Prior MRI-PBx is thus a predictor for successful nerve-sparing RARP approach. CONCLUSION: Preoperative MRI-PBx led to better oncological outcomes and less SNR. Young patients with good erectile function could benefit from a preoperative MRI-PBx before nerve-sparing RARP.

Mapping a Danger Zone of the Dorsal Nerve of the Clitoris: Implications in Female Cosmetic Genital Surgery.

BACKGROUND: The literature regarding the route of the dorsal nerve of the clitoris is sparse and lacks surgical focus. With an increasing number of procedures being performed on the labia, it is important to elucidate the route and note any variation from normal of the nerve. METHODS: Fifty-one cadavers were dissected to yield 97 dorsal nerve of the clitoris samples. Measurements were taken from (1) the dorsal nerve of the clitoris penetration point of the perineal membrane to the urethra, (2) the nerve's penetration point of the perineal membrane to the pubic bone, (3) the angle of the clitoris to the branch point of the dorsal nerve of the clitoris, and (4) the branch point of the nerve to the distalmost point of the glans clitoris. Any anomalous branching patterns of the dorsal nerve of the clitoris were recorded and classified. RESULTS: The means and standard deviations of each measurement were used to create a surgical danger zone. The mean of each measurement was (1) 34.63 mm, (2) 5.74 mm, (3) -3.07 mm, and (4) 30.40 mm, respectively. In addition, six distinct branching patterns were observed, organized, and classified based on the location and number of branches observed. CONCLUSIONS: The dorsal nerve of the clitoris has multiple branching patterns and typically travels along the same course in most women. Further investigation of the course and three-dimensional position of the dorsal nerve of the clitoris is warranted to preserve sexual sensation as the frequency of procedures involving the female pudendum increases.

Overexpression of miR-378 Alleviates Chronic Sciatic Nerve Injury by Targeting EZH2.

In numerous studies, microRNAs (miRNAs) have been authenticated to play vital roles in the pathophysiology of neuropathic pain and other neurological diseases. In our study, we focused on evaluating miR-378 and its potential effects in neuropathic pain development, as well as the underlying molecular mechanisms. Primarily, a chronic sciatic nerve injury (CCI) rat model was established. Next, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was employed to measure the expression levels of miR-378 and EZH2 mRNA; the EZH2 protein expression levels were detected by western blot. A luciferase activity assay monitored the interaction of miR-378 and EZH2. Mechanical and thermal hyperalgesia was also performed to quantitate the effects of overexpression of miR-378 or EZH2 on the CCI rats. We found that miR-378 was down-regulated in the CCI rats, and the overexpression of miR-378 produced significant relief in their pain management. EZH2 was the downstream gene of miR-378 and was negatively regulated by miR-378. The up-regulation of EZH2 reduced the inhibitory effects of miR-378 on the development of neuropathic pain in the CCI rats. miR-378 acts as an inhibitor in the progression of neuropathic pain via targeting EZH2; the miR-378/EZH2 axis may be a novel target for the diagnosis and therapy of neuropathic pain in clinical treatment.

Comparison of lateral entry and crossed entry pinning for pediatric supracondylar humeral fractures: a meta-analysis of randomized controlled trials.

BACKGROUND: Closed reduction and pinning entry fixation have been proposed as treatment strategies for displaced supracondylar humeral fractures (SCHFs) in children. However, controversy exists regarding the selection of the appropriate procedure. Hence, this meta-analysis was conducted to compare the effect of lateral and crossed pin fixation for pediatric SCHFs, providing a reference for clinical treatment. METHODS: Online databases were systematically searched for randomized controlled trials (RCTs) comparing lateral pinning entry and crossed pinning entry for children with SCHFs. The primary endpoints were iatrogenic ulnar nerve injuries, complications, and radiographic and functional outcomes. RESULTS: Our results showed that iatrogenic ulnar nerve injuries occurred more commonly in the crossed pinning entry group than in the lateral pinning entry group (RR = 4.41, 95% CI 1.97-9.86, P < 0.05). However, its risk between the crossed pinning with mini-open incisions group and the lateral pinning entry group was not significantly different (RR = 1.58, 95% CI 0.008-29.57, P = 0.76). The loss of reduction risk was higher in the lateral pinning entry group than in the crossed pinning entry group (RR = 0.66; 95% CI 0.49-0.89, P < 0.05). There were no significant differences in the carry angle, Baumann angle, Flynn scores, infections, and other complications between these two groups. CONCLUSIONS: The crossed pinning entry with mini-open incision technique reduced the loss of reduction risk, and the risk of iatrogenic ulnar nerve injury was lower than in the lateral pinning entry group. The crossed pinning entry with mini-open incision technique is an effective therapeutic strategy for managing displaced supracondylar humeral fractures in children.

Prevention and Treatment of Nerve Injuries in Shoulder Arthroplasty.

➤: Nerve injuries during shoulder arthroplasty have traditionally been considered rare events, but recent electrodiagnostic studies have shown that intraoperative nerve trauma is relatively common. ➤: The brachial plexus and axillary and suprascapular nerves are the most commonly injured neurologic structures, with the radial and musculocutaneous nerves being less common sites of injury. ➤: Specific measures taken during the surgical approach, component implantation, and revision surgery may help to prevent direct nerve injury. Intraoperative positioning maneuvers and arm lengthening warrant consideration to minimize indirect injuries. ➤: Suspected nerve injuries should be investigated with electromyography preferably at 6 weeks and no later than 3 months postoperatively, allowing for primary reconstruction within 3 to 6 months of injury when indicated. Primary reconstructive options include neurolysis, direct nerve repair, nerve grafting, and nerve transfers. ➤: Secondary reconstruction is preferred for injuries presenting >12 months after surgery. Secondary reconstructive options with favorable outcomes include tendon transfers and free functioning muscle transfers.

A modified oblique incision in hamstring tendon graft harvesting during ACL reconstruction.

BACKGROUND: During anterior cruciate ligament (ACL) reconstruction, different methods of harvesting hamstring tendon may lead to different degrees of injury to the inferior patellar branch of the saphenous nerve (IPBSN). Most of recent studies in the literature suggest that the classic oblique incision (COI) can reduce the incidence of IPBSN injury. We proposed a modified oblique incision (MOI) and compared it with the COI in terms of the resulting levels of injury and sensory loss and the clinical outcome. METHODS: Patients with ACL injury admitted to our hospital from April 2015 to July 2019 were randomly selected and included in our study. Thirty patients underwent the COI to harvest hamstring tendons, and the other 32 patients underwent the MOI. The pin prick test was performed to detect the sensation loss at 2 weeks, 6 months, and 1 year after the operation. Digital photos of the region of hypoesthesia area were taken, and then, a computer software (Adobe Photoshop CS6, 13.0.1) was used to calculate the area of the hypoesthesia. The length of the incision and knee joint functional score were also recorded. RESULTS: At the final follow-up, the incidence of IPBSN injury in COI and MOI were 33.3% and 9.4%, and the areas of paresthesia were 26.4±2.4 cm2 and 9.8±3.4 cm2 respectively. There was no significant difference in the incision length or knee functional score between the two groups. CONCLUSION: The MOI can significantly reduce the risk of injury to the IPBSN, reduce the area of hypoesthesia, and lead to high subjective satisfaction. Therefore, compared with the COI, the MOI is a better method of harvesting hamstring tendons in ACL reconstruction.

The anatomical relationship of the common peroneal nerve to the proximal fibula and its clinical significance when performing fibular-based posterolateral reconstructions.

PURPOSE: The common peroneal nerve (CPN) can be injured during fibular-based posterolateral reconstructions due to its close relationship to the neck of the fibula. Therefore, the purpose of this study was to observe the course of the CPN and its branches around the fibular head and neck and quantify the position in relation to relevant bony landmarks and observe the relation between tunnel drilling for posterolateral corner reconstruction and both the tunnel entry and exit at the proximal fibula and the CPN and its branches was observed. METHODS: In 101 (mean age = 70.6 ± 16 years) embalmed cadaver knees, the relationship between bony landmarks (tibial tuberosity, styloid process of fibula (APR)) and the CPN and its branches were established and 8 (M1-M8) distances from these landmarks measured; mean, SD and 95% CI were recorded. In 21 of these knees, a fibula tunnel was drilled as in PLC reconstruction and the association of the CPN and its branches to the tunnel entry and exit were judged by two independent observers. Fisher's exact test of independence was used to determine significant differences between genders. Tunnel intersection was analysed in a binary yes/no fashion and was described in frequencies and percentages. RESULTS: The mean distance from the APR to where the CPN reaches the fibula neck (M1) was 31.4 ± 8.9 mm (CI:29.8-33.0); from the apex of the styloid process (APR) to where the CPN passes posterior to the broadest point of the fibular head (M3) was 21.7 ± 12.6 mm (CI:19.4-24.0); from the apex of the APR to the most proximal point of the CPN/CPN first branch in the midline of the fibular head (M2) was 37.0 ± 6.7 mm (CI: 35.4-37.7). Out of the 21 randomly selected knees for drilling, the first branch of the CPN was damaged at the tunnel entry point in 7 (33%), and in 5 knees (24%), the CPN was damaged at the tunnel exit. In one knee, at both the tunnel entry and exit, the first branch of the CPN and the CPN were intersected, respectively. CONCLUSION: The results of this study strongly suggest that the CPN is at risk when drilling the fibula tunnel performing fibula-based posterolateral corner reconstructions. The total injury rate was 57% with a 33% incidence of injury to the first branch of the nerve at the tunnel entry and 24% to the CPN at the tunnel exit. CLINICAL RELEVANCE: Due to the high incidence of injury, percutaneous placement of guide pins and tunnel drilling is not recommended. The nerve should be visualized and protected by either a traditional open approach or minimally invasive techniques. With a minimally invasive approach, the nerve should be identified at the fibula neck and then followed ante- and retrograde.

Surgical anatomy of the radial nerve in the anterior compartment of the arm: relationship with the triceps aponeurosis.

PURPOSE: Injury to the radial nerve is not an uncommon phenomenon in fracture displacement of distal humerus and its operative management as the nerve is immobile and superficial at its point of entry into the anterior compartment and in close proximity to humerus. Such injuries can be reduced by defining a 'safe area' for the radial nerve in relation to the triceps aponeurosis in the distal humerus. METHODS: Radial nerve was dissected in 40 arms and distance of the nerve from triceps aponeurosis was measured at five sites; first one at the level of proximal or medial apex of aponeurosis, followed by four sites along its lateral border. These distances were analyzed to identify its location and to define a 'safe area' in relation to the triceps aponeurosis in the distal humerus. RESULTS: In majority of cases (67.50%), the point of entry of radial nerve into anterior compartment was at the level of proximal or medial apex at a mean distance of 2.11 ± 0.31 cm. The mean distance of radial nerve from the lateral border of triceps aponeurosis was 1.98 ± 0.60 cm with a range of 1.00-2.50 cm. The closest distance between the nerve and the aponeurosis was found to be 1.00 cm at the level of distal or lateral apex. CONCLUSION: The relationship between radial nerve and triceps aponeurosis is constant and easily reproducible. It is suggested that the rectangular zone immediately adjoining the lateral border of aponeurosis (< 1.00 cm) can be considered "safe" for soft tissue dissection while surgically approaching distal humeral fractures.

Relocating the C5 nerve stump in C5 nerve grafting to prevent iatrogenic phrenic nerve injury.

BACKGROUND: Exploration and grafting of the brachial plexus remains the gold standard for post-ganglionic brachial plexus injuries that present within an acceptable time frame from injury. The most common nerves available for grafting include C5 and C6. During the surgical exposure of C5 and C6, the phrenic nerve is anatomically anterior to the cervical spinal nerves, making it vulnerable to injury while performing the dissection and nerve stump to graft coaptation. We describe a novel technique that protects the phrenic nerve from injury during supraclavicular brachial plexus exposure and grafting of C5 or upper trunk ruptures or neuromas in-continuity. METHODS: A 4-step technique is illustrated: (1) The normal anatomic relationships of the phrenic nerve anterior to C5 is displayed in the face of the traumatic scarring. (2) The C5 spinal nerve stump is then transposed from its anatomic position posterior to the phrenic nerve to an anterior position. (3) The C5 stump is then moved medially for retrograde neurolysis of C5 from its phrenic nerve contribution. The graft coaptation to C5 is performed in this medial position, which minimizes retraction of the phrenic nerve. (4) The normal anatomic relationship of the phrenic nerve and the C5 nerve graft is restored. RESULTS: We have been routinely relocating the C5 spinal nerve stump around the phrenic nerve for the past 10 years. We have experienced no adverse respiratory events. CONCLUSION: This technique facilitates surgical exposure and prevents iatrogenic injury on the phrenic nerve during nerve reconstruction.

Structures at Risk During Percutaneous Extra-Articular Chevron Osteotomy of the Distal First Metatarsal.

Background. Minimally invasive surgery of the forefoot has regained popularity as an alternative to traditional open procedures. Minimally invasive hallux valgus surgery has been shown to be effective and reproducible for the treatment of mild to moderate hallux valgus. The aim of this study is to identify vital structures that are at risk for iatrogenic damage while performing a minimally invasive distal chevron osteotomy due to limited direct visualization. Methods. Ten fresh-frozen below knee cadavers were used for this study. A minimally invasive distal chevron osteotomy and medial eminence resection with a 2.2 mm × 22 mm Shannon burr was performed on each cadaver. Each specimen was dissected to expose the potential structures at risk for injury during the procedure. Structures evaluated included the medial neurovascular bundle, first metatarsophalangeal joint capsule, extensor hallucis longus tendon, flexor hallucis longus tendon, abductor hallucis tendon, and the sesamoid apparatus. Results. Ten specimens were evaluated. The dorsal medial cutaneous nerve was directly injured in 5 of the 10 cadaver specimens and intact/uninjured in the remaining 5 specimens. The flexor hallucis longus, extensor hallucis longus, adductor tendon, sesamoid apparatus, and first metatarsophalangeal joint capsule were uninjured in all specimens. Conclusion. Minimally invasive chevron distal osteotomy and medial eminence resection has a high learning curve. The resection of the medial eminence may iatrogenically injure the dorsal medial cutaneous nerve. The incidence is higher in this study than prior reported cadaveric studies and may warrant extra care to protect vital structures.Level of Evidence: Level IV: Cadaver study.

Assessments of regenerative potential of silymarin nanoparticles loaded into chitosan conduit on peripheral nerve regeneration: a transected sciatic nerve model in rat.

PURPOSE: It is compulsory to make a tension-free, end-to-end repair in transected injuries. However, when it comes to longer defects, placement of an autograft or nerve conduits is required. The present study was designed to assess regenerative potential of silymarin nanoparticles loaded into chitosan conduit on peripheral nerve regeneration in a transected sciatic nerve model in rat. METHODS: In NML group left sciatic nerve was exposed through a gluteal muscle incision and after careful hemostasis skin was closed. In TSC group left sciatic nerve was transected and stumps were fixed in adjacent muscle. In CTN group, 10-mm sciatic nerve defects were bridged using a chitosan. In CTN/NSLM group, 10-mm sciatic nerve defects were bridged using a chitosan conduit and 100 µL silymarin nanoparticles were administered into the conduit. The regenerated fibers were studied 4, 8, and 12 weeks after surgery. Assessment of nerve regeneration was based on behavioral, functional, biomechanical, histomorphometric, and immuohistochemical criteria. RESULTS: The behavioral, functional, electrophysiological, and biomechanical studies confirmed significant recovery of regenerated axons in CTN/NSLM group (P < 0.05). Quantitative morphometric analyses of regenerated fibers showed number and diameter of myelinated fibers in CTN/NSLM group were significantly higher than in CTN group (P < 0.05). DISCUSSION: This demonstrated potential of using chitosan-silymarin nanoparticles in peripheral nerve regeneration without limitations of donor-site morbidity associated with isolation of autograft. It is also cost saving and may have clinical implications for surgical management of patients after peripheral nerve transection.