Variations ignored in routine wrist MRI reports: prevalence of the median nerve anatomical variations and persistent median artery.

BACKGROUND: It is vital to know the anatomical variations of the wrist to avoid iatrogenic injuries during carpal tunnel (CT) surgery. PURPOSE: To determine the anatomical variations of the median nerve (MN) and the prevalence of persistent median artery (PMA) on wrist magnetic resonance imaging (MRI). MATERIAL AND METHODS: A total of 300 wrists evaluated by MRI during 2013-2015 were retrospectively identified. While branching of the MN distal to the CT is accepted as the normal anatomy, proximal to the tunnel and within the tunnel were considered as variations. The prevalence of PMA was also evaluated. The patients were assigned to groups according to age, gender, and wrist side and compared to determine whether there was any significant difference in terms of these variations. All evaluations were assessed with the shared decision of a musculoskeletal radiologist and a radiology resident. RESULTS: Of the 300 wrists, 38 (12.7%) and 34 (11.3%) had a bifid MN proximal to the CT and within the CT, respectively. Only one nerve trifurcation was seen within the CT. The MN exhibited branching distal to the CT in 227 (76%) patients. PMA was observed in 44 (14.7%) patients. Of the 44 PMA cases, 28 (63.6%) also had a coexisting MN variation. There was no significant difference in the prevalence of MN variations and PMA in the subgroups (P > 0.05). CONCLUSION: Nearly one in four patients (24.4%) have MN variations and 14.8% had PMA. Preoperative evaluation of these common anatomical variations with MRI will be protective against postoperative complications of CT surgery.

Monitoring the Patient Following Radio-Cephalic Arteriovenous Fistula Creation: Current Perspectives.

Autogenous radial-cephalic direct wrist arteriovenous fistula (RC-AVF) in the non-dominant arm is the gold standard for dialysis vascular access. However, the RC-AVF non-maturation rate is significant (≃ 40%) due to an increasingly elderly and comorbid population incidence. A detailed identification of the biological cascade underlying arteriovenous fistula (AVF) maturation could be the key to clinical research aimed at identify the group of patients at risk of primary AVF failure. Currently, careful post-operative monitoring remains the most crucial aspect to overcome the problem of impaired maturation. Up to 80% of patients with immature RC-AVF have problems potentially solvable with early endovascular or surgical correction. Physical examination by experienced practitioners in conjunction with duplex ultrasound examination (DUS) can identify physical signs of non-maturation, understand the underlying cause, and drive for a tailored early planning to treat the complication. New approaches for the early assessment of AVF maturation are under study. Techniques to promote RC-AVF maturation performed through the administration of pre-or peri-operative drugs have missed up to now to prove an efficacy in improving fistula success. The new techniques tested after surgery appear to hold future promise for improving fistula maturation.

Contemporary outcomes of a "snuffbox first" hemodialysis access approach in the United States.

OBJECTIVE: The Society for Vascular Surgery guidelines for permanent hemodialysis (HD) access creation recommend prioritizing the most distal possible autogenous access to minimize complications and preserve more proximal options. The "snuffbox" arteriovenous fistula (AVF) is the most distal radial artery-cephalic vein AVF. Despite the theoretical benefits of the snuffbox approach, recent trends have been toward upper arm access. Our study sought to investigate the feasibility of a snuffbox-first strategy for HD access in all anatomically appropriate candidates. METHODS: From January 2016 to August 2019, all patients with end-stage renal disease (ESRD) or pre-ESRD under consideration for HD access were evaluated for a snuffbox-first approach by a team of vascular surgeons and nephrologists at a single, urban academic medical center in the United States. Data were collected prospectively and supplemented by medical record review. A survival analysis was performed to evaluate primary unassisted and secondary patency and clinical and functional maturation. Patients were censored if they had received a kidney transplant or had died. Cox proportional hazards regression was used to determine the risk factors for prolonged clinical maturation and functional maturation. RESULTS: A total of 55 snuffbox AVFs were created. The median patient age was 60 years (interquartile range [IQR], 52-70 years), and 52.7% of the patients were men. The median follow-up was 369 days (IQR, 166-509 days). The median survival for primary unassisted patency was 90 days (95% confidence interval [CI], 79-111). Secondary patency at 1 year was 92.3% (95% CI, 85.3%-99.9%). The clinical maturation rate at 1 year was 83.7% (n = 55; 95% CI, 66.8%-91.9%), and the functional maturation rate at 1 year was 85.6% (n = 40; 95% CI, 63.3%-94.4%). Of the patients who were pre-ESRD at AVF creation and had initiated HD during the study period, 87.5% had successfully received incident HD with their snuffbox AVF. Twenty-four patients were receiving HD via a catheter at snuffbox creation. Of those patients, the functional maturation rate at 1 year was 82.5% (95% CI, 44.8%-94.4%). The patients had undergone a median of two interventions (IQR, zero to seven interventions) in the first year. Of these, 46.9% were percutaneous angioplasty and 31.2% were side-branch ligation. Diabetes was associated with slower AVF clinical maturation (multivariate hazard ratio, 0.35; 95% CI, 0.15-0.82; P = .016). A larger artery diameter was associated with earlier AVF clinical maturation (multivariate hazard ratio, 6.64; 95% CI, 2.11-20.9). CONCLUSIONS: A snuffbox-first approach to HD access is a viable option for distal access creation in a cohort of patients requiring HD in the United States. Subsequent ancillary interventions to facilitate access maturation were required for most patients.

Effects of Photobiomodulation Therapy and Restriction of Wrist Extensor Blood Flow on Grip: Randomized Clinical Trial.

Objective: To evaluate the influence of two different photobiomodulation therapy (PBMT) protocols (red 660 nm vs. infrared 830 nm) combined with a blood flow restriction (BFR) training protocol in wrist extensor muscles on handgrip, wrist extension force, and electromyographic behavior [root mean square (RMS)]. Background: PBMT has been widely used to increase muscle performance and recovery in recent clinical trials. However, there is no evidence whether PBMT (red and/or infrared) can promote better results when combined with BFR, a known method to induce better strength gains. Methods: This study was a randomized controlled trial including 58 volunteers allocated into four groups: (1) control (conventional strengthening), (2) BFR (strengthening with BFR), (3) 660 nm (BFR strengthening with 660 nm PBMT-35 mW; 0.05 cm2; 2.10 J, total energy 18.9 J), and (4) 830 nm (BFR strengthening with 830 nm PBMT-32 mW; 0.101 cm2; 1.92 J, total energy 17.2 J). Data were analyzed by using a mixed-effects model, with a 5% significance index. Results: A statistically significant increase was obtained for handgrip strength for the 660 nm group [27.36 ± 2.61 kilogram force (kgF)] compared with the 830 nm group (23.04 ± 3.06 kgF) (p = 0.010) and for wrist extensor strength in the 660 nm (7.77 ± 0.58 kgF) and BFR (7.54 ± 0.92 kgF) groups compared with the control group (5.33 ± 0.61 kgF) (p = 0.001 and p = 0.004, respectively). The RMS value for the 660 nm group was significantly higher than control (p < 0.0001), BFR (p < 0.0001), and the 830 nm group (p = 0.0009). Conclusions: The association of PBMT (660 nm) and BFR was effective for increasing handgrip strength of the wrist extensors, associated with an increase in RMS.

Venous distensibility is more important than venous diameter in primary survival of autogenous radiocephalic arteriovenous fistulas.

BACKGROUND: Many studies suggested that the optimal cephalic vein diameter for wrist radio-cephalic arteriovenous fistula construction should be at least 2 mm to predict successful maturation and primary patency. However, our experience has shown that many patients with smaller cephalic vein diameter (≤2 mm) in the neutral state (without a tourniquet) also have good clinical outcomes. The aim of this study was to identify predictors that affect primary survival of new wrist radio-cephalic arteriovenous fistula in patients with cephalic vein diameter ≤2 mm. METHODS: We performed a retrospective review of 50 patients with preoperative cephalic vein diameters ≤2 mm in the neutral state who underwent wrist radio-cephalic arteriovenous fistula construction between September 2016 and October 2019. Internal diameters of the cephalic vein and radial artery, venous distensibility, peak systolic velocity, and resistance index of the radial artery were determined by ultrasound examination before wrist radio-cephalic arteriovenous fistula placement. Patients were divided into two groups: failure and survival. RESULTS: The radio-cephalic arteriovenous fistula survival rate was 68% from the time of radio-cephalic arteriovenous fistula creation until the end of the study. Univariate analysis showed that larger venous distensibility (p < 0.001), non-diabetic kidney disease (p = 0.009), and slower peak systolic velocity of the radial artery (p = 0.033) were predictive factors for primary radio-cephalic arteriovenous fistula survival. Multivariate regression analysis revealed good venous distensibility (odds ratio = 9.637, 95% confidence interval = 1.893-49.050, p = 0.006) and non-diabetic kidney disease (odds ratio = 0.148, 95% confidence interval = 0.033-0.660, p = 0.012) to be independent predictors for primary radio-cephalic arteriovenous fistula survival. Receiver operating characteristic analysis showed that venous distensibility >0.52 mm (sensitivity: 70.6%, specificity: 68.8%) was the best cut-off value to predict primary radio-cephalic arteriovenous fistula survival. CONCLUSION: When cephalic veins with diameter ≤2 mm are found, venous distensibility should be used to aid in the surgery decision-making process. The outcome of wrist radio-cephalic arteriovenous fistula survival would be significantly improved through the use of cephalic vein with venous distensibility >0.52 mm.

Usefulness of Ramified Cephalic Vein Graft in the Wrist for Connection With Concomitant Vein in Head and Neck Reconstruction.

A vein graft in head and neck reconstruction is essential in some circumstances. The cephalic vein in the wrist has a suitable caliber for both a concomitant vein and the internal jugular vein (IJV). A vein graft involving the cephalic vein and its branches was used in 2 cases of head and neck reconstruction. The ramified distal vein was anatomized with a concomitant vein, and the proximal larger vein was anastomosed with the IJV using an end-to-side technique. After placement of vein grafts using the cephalic vein, the flaps were stable with no venous complications. To overcome the size difference between concomitant veins and the IJV, the authors recommend the cephalic vein including its distal branches in the wrist area.

Preoperative cephalic vein diameter and diabetes do not limit the choice of wrist radio-cephalic arteriovenous fistula.

AIM: To identify predictors that affect initial maturation of new wrist radio-cephalic arteriovenous fistula and evaluate the clinical effects of the ipsilateral mid-forearm radio-cephalic arteriovenous fistulas creation in the event of first wrist radio-cephalic arteriovenous fistula failure. METHODS: We performed a retrospective review of all patients who underwent first wrist radio-cephalic arteriovenous fistula creation between September 2016 and May 2018. Currently, we prefer to re-create an ipsilateral mid-forearm radio-cephalic arteriovenous fistula when the first wrist radio-cephalic arteriovenous fistula fails. Predictors of successful radio-cephalic arteriovenous fistulas were identified using univariate and multivariate analyses. Kaplan-Meier survival analysis and log-rank test were used to calculate successful radio-cephalic arteriovenous fistula rates. RESULTS: Univariate analysis showed that predictive factors for successful wrist radio-cephalic arteriovenous fistula include larger preoperative cephalic vein diameter (p = 0.001) and non-diabetic kidney disease (p = 0.007). Multivariate binary logistic regression analysis revealed cephalic vein diameter ⩾2 mm (odds ratio = 4.55, 95% confidence interval = (1.49-13.92), p = 0.008) and non-diabetic kidney disease (odds ratio = 4.22, 95% confidence interval = (1.38-12.88), p = 0.011) to be independent predictors for successful radio-cephalic arteriovenous fistula. We re-created ipsilateral mid-forearm radio-cephalic arteriovenous fistulas in 15 patients among the 21 failed wrist radio-cephalic arteriovenous fistulas; all these arteriovenous fistulas maintained clinical maturation following up for 1-2 years. CONCLUSION: Small cephalic vein diameter (<2 mm) and diabetes were independent risk factors for failed wrist radio-cephalic arteriovenous fistulas, but this risk could be overcome by aggressive ipsilateral mid-forearm radio-cephalic arteriovenous fistula to address a failed first attempt. Cephalic vein diameter is more important during the maturation stage, and once maturation has occurred, diabetes has an additive role in determining the patency of wrist radio-cephalic arteriovenous fistula. The "wrist RCAVF first, ipsilateral mid-forearm RCAVF second" strategy is the most clinically significant message of our study.

Snuffbox arteriovenous fistulas have similar outcomes and patency as wrist arteriovenous fistulas.

OBJECTIVE: Radial artery-based wrist arteriovenous fistulas (AVFs) are commonly created as an initial upper extremity arteriovenous access. A more distal access site, such as the anatomic snuffbox AVF, can also be created. Although much has been written about wrist AVFs, outcomes of snuffbox AVFs are unclear. Our goal was to compare perioperative and midterm outcomes between these two types of distal access. METHODS: The Vascular Quality Initiative database was queried for all patients undergoing snuffbox AVFs and wrist AVFs from 2011 to 2017. Unmatched and matched analyses were performed for baseline characteristics and outcomes at 6 months for ischemic steal, wound infection, and arm swelling. Multivariable analysis was performed for unmatched and matched analyses for primary patency, surgical or endovascular repair, and patient survival. Kaplan-Meier matched analysis was performed for primary patency, freedom from surgical or endovascular intervention, and survival. RESULTS: We identified 4525 distal forearm fistulas: 179 (4%) snuffbox AVFs and 4346 (96%) wrist AVFs. The average age was 59 ± 14.7 years, and 72.3% of patients were male. There were no significant differences in baseline demographics or comorbidities of patients with snuffbox AVFs and wrist AVFs except that patients with snuffbox AVFs had fewer tunneled lines at access creation (70.2% vs 65.2%; P = .046) and had a lower American Society of Anesthesiologists class. There were no significant differences in unmatched outcomes at 6 months for ischemic steal (0.8% vs 1.9%; P = .336), wound infection (0% vs 0.2%; P = .649), and arm swelling (0.8% vs 1.3%; P = .592). Matched analysis showed no significant differences in baseline characteristics and outcomes at 6 months for ischemic steal (0% vs 1.8%; P = .146), wound infection (0% vs 0%), and arm swelling (0.9% vs 1.2%; P = .789). Kaplan-Meier matched analysis showed no significant differences between snuffbox AVFs and wrist AVFs at 6 months for primary patency (51% vs 48%; P = .61), freedom from endovascular intervention (84.5% vs 82.5%; P = .98), freedom from surgical intervention (90% vs 86%; P = .08), and survival (92% vs 96%; P = .1). In multivariable analysis of unmatched data, snuffbox AVFs and wrist AVFs had similar primary patency (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.75-1.26; P = .83), likelihood of surgical intervention (HR, 0.61; 95% CI, 0.35-1.05; P = .074) and endovascular intervention (HR, 0.96; 95% CI, 0.65-1.42; P = .83), and survival (HR, 1.47; 95% CI, 0.9-2.4; P = .128). CONCLUSIONS: Snuffbox AVFs have midterm results similar to those of wrist AVFs.

Two weeks post-operative ultrasound examination of radio-cephalic arteriovenous fistulae to predict maturity in a Chinese population.

AIM: The aim of this study was to assess the accuracy of post-operative ultrasound examination for predicting wrist radio-cephalic arteriovenous fistula maturity. METHODS: All radio-cephalic arteriovenous fistulas performed in our hospital between October 2015 and December 2017 were included in this study. Ultrasound examination of radio-cephalic arteriovenous fistulas was performed 2 weeks post-surgery. Radio-cephalic arteriovenous fistula maturation was defined as successful cannulation of a fistula with two needles, delivery of blood via the access route at a flow rate ⩾200 mL/min for 4 h, and dialysis via fistulae in at least six consecutive sessions. RESULTS: Eighty-two wrist radio-cephalic arteriovenous fistulas were analyzed, of which 13 failed. Cephalic vein diameter >4.285 mm and brachial artery peak systolic velocity >134.75 cm/s were the best post-operative ultrasound predictors of radio-cephalic arteriovenous fistula maturity (p < 0.001 and p = 0.011, respectively). Receiver-operating characteristic curve analysis showed that the sensitivity and specificity of predicting radio-cephalic arteriovenous fistula maturation were 88.4% and 92.3% for cephalic vein diameter (area under the curve = 0.939), respectively, and 82.9% and 76.9% for brachial artery peak systolic velocity (area under the curve = 0.830), respectively. All assessments predicted radio-cephalic arteriovenous fistula maturity (post-operative positive predictive values: cephalic vein diameter = 98.4%, brachial artery peak systolic velocity = 95%) much better than radio-cephalic arteriovenous fistula failure (post-operative negative predictive values: cephalic vein diameter = 60%, brachial artery peak systolic velocity = 45.5%). CONCLUSION: Two weeks after surgery, a new wrist radio-cephalic arteriovenous fistula with a cephalic vein diameter >4.285 mm was considered suitable for dialysis. A high-risk arteriovenous fistula failure would benefit from early intervention.

A Rare Pediatric Case of Posttraumatic Pseudoaneurysm: Case Report and Literature Review.

Posttraumatic pseudoaneurysms are extremely rare in pediatric populations. In many cases, pseudoaneurysms may be confused with abscesses, epidermoid cysts, arteriovenous fistula, foreign objects, and ganglion cysts, as well as tumors. They are associated with distinguishing findings of "pulsatile mass, a palpable thrill, and an audible to-and-fro murmur" (1), which can be confirmed by various imaging techniques. In this report, we describe the case of a 4-year-old boy who presented to the pediatric emergency department 3 weeks after falling and subsequently getting cut by glass. Upon clinical examination, the patient presented with pulsatile, swollen mass in the left wrist. A Doppler ultrasound of the left wrist demonstrated that the area of clinical concern in the left wrist showed a pseudoaneurysm, and prominent arterial blood flow was seen within the pseudoaneurysm. Because pseudoaneurysms, particularly posttraumatic pseudoaneurysms, are extremely rare in the pediatric population, it may be easy to miss these cases during clinical examination. Misdiagnosis of the pseudoaneurysm can cause delayed treatment, a longer recovery period, and complications such as infection, rupture, and hemorrhage. It is important for physicians to consider this entity when evaluating patients with symptoms of asymptomatic bulges to painful pulsatile masses after trauma.

A Rare Case of Brachial Artery Aneurysm Following Hemodialysis Fistula Ligation in a Transplanted Patient.

Aneurysmal arterial dilatation is an infrequent complication following arteriovenous fistula ligation. Herein, we are describing a case in which a 49-year-old transplanted patient developed a true, symptomatic, brachial artery aneurysm 25 years after transplantation and 12 years after ligation of his radiocephalic wrist fistula. Treating strategy included aneurysmectomy and reversed vein interposition using ipsilateral, dilated branch of cephalic vein. Two years postoperatively, the patient remains without complications. Moreover, we mention the pathophysiologic mechanisms that may have contributed to this phenomenon.

Adventitial Cystic Disease of the Radial Artery.

Upper extremity adventitial cystic disease is rare, but the characteristic findings of this lesion should be known to the hand surgeon and used to guide treatment. We present a case of a young adult male who developed a painless mass in his distal forearm. Diagnostic imaging workup revealed a cystic mass that extended within and encased the radial artery. Both MRI and direct intraoperative visualization confirmed the presence of a stalk connecting the intra-mural radial artery mass to the radiocarpal joint. The mass and stalk were excised en bloc with fenestration of the volar capsule to prevent recurrence. This case demonstrates a less common example of upper extremity adventitial cystic disease and supports the articular theory of origin of these lesions. When surgical excision is performed, an attempt should be made to identify and excise the articular stalk in an effort to minimize risk of recurrence.

Cephalic venous aneurysm in the wrist.

Venous aneurysms are benign vascular lesions usually located in the neck, lower extremity, and abdomen, but rarely in the upper extremity. There may be a mistake or delay in diagnosis because they are uncommon. We report a case of a healthy 54-year-old man who had a cephalic venous aneurysm in his wrist that grew slowly over 20 years. The diagnosis was made on MRI and confirmed with excisional surgery. Radiologists should consider venous aneurysms in the differential when evaluating soft tissue masses as they will often be the first to make the correct diagnosis.

A Methodology for Non-Invasive 3-D Surveillance of Arteriovenous Fistulae Using Freehand Ultrasound.

OBJECTIVE: Surveillance techniques for arteriovenous fistulae are required to maintain functional vascular access, with two-dimensional duplex ultrasound the most widely used imaging modality. This paper presents a surveillance method for an arteriovenous fistula using a freehand three-dimensional (3-D) ultrasound system. A patient-case study highlights the applicability in a clinical environment. METHODS: The freehand ultrasound system uses optical tracking to determine the vascular probe location, and as the probe is swept down a patient's arm, each B-mode slice is spatially arranged to be post-processed as a volume. The volume is segmented to obtain the 3-D vasculature for high detail analysis. RESULTS: The results follow a patient with stenosis, undergoing surgery to have a stent placement. A surveillance scan was taken pre-surgery, postsurgery, and at a two-month follow-up. Vasculature changes are quantified using detailed analysis, and the benefits of using 3-D imaging are shown through 3-D printing and visualization. CONCLUSION AND SIGNIFICANCE: Non-invasive 3-D surveillance of arteriovenous fistulae is possible, and a patient-specific geometry was created using ultrasound and optical tracking. Access to this non-invasive 3-D surveillance technique will enable future studies to determine patient-specific remodeling behavior, in terms of geometry and hemodynamics over time.

Creation of an Arterialized Cephalic Vein as Autologous Bypass for Below-Knee Reconstruction in Critical Limb Ischemia.

Two cases of below-knee bypasses using an arterialized cephalic vein (CV) are presented. Both patients had critical ischemia, but no greater or lesser saphenous veins (LSVs) were usable. According to ultrasound, the CVs were thin but regularly positioned. Four weeks after wrist fistula was created, ultrasound showed adequate maturation, and the bypass operations were performed. Both patients had uneventful courses and were discharged after a few days with patent bypasses since then (35 and 18 months). As this report shows, creation of a fistula can be a useful option to gain autologous bypass material in case of critical limb ischemia.

Microsurgery for "wrist" arteriovenous fistula creation in children: a retrospective cohort study.

INTRODUCTION: Creating functional arteriovenous fistulae (AVF) at the wrist is challenging in paediatric patients because of the small calibre of the blood vessels. METHODS: We report our experience with AVF surgery in children younger than 15 years of age using microsurgical techniques. Twenty-five patients underwent AVF surgery between 2003 and 2015 (20 for haemodialysis, 4 for plasmapheresis and 1 for parenteral nutrition). Median (range) age was 9 (2-15) years and median weight was 24 (8-61) kg. RESULTS: The one-month occlusion rate was 8%. The primary and secondary patency rates at 1, 2, 3 years were: 60%, 49%, 42%, and 82%, 72%, 54%, respectively. The median (range) maturation time was 4.53 (0.5-11.2) months. We found no statistically significant effect of patient age, body weight, type of AVF and indication for AVF creation on the primary and secondary patency rates. CONCLUSIONS: Microsurgical AVF creation at the wrist can be performed with satisfactory results and should be the preferred technique in the paediatric population.

First-in-Human Study of Acoustic Angiography in the Breast and Peripheral Vasculature.

Screening with mammography has been found to increase breast cancer survival rates by about 20%. However, the current system in which mammography is used to direct patients toward biopsy or surgical excision also results in relatively high rates of unnecessary biopsy, as 66.8% of biopsies are benign. A non-ionizing radiation imaging approach with increased specificity might reduce the rate of unnecessary biopsies. Quantifying the vascular characteristics within and surrounding lesions represents one potential target for assessing likelihood of malignancy via imaging. In this clinical note, we describe the translation of a contrast-enhanced ultrasound technique, acoustic angiography, to human imaging. We illustrate the feasibility of this technique with initial studies in imaging the hand, wrist and breast using Definity microbubble contrast agent and a mechanically steered prototype dual-frequency transducer in healthy volunteers. Finally, this approach was used to image pre-biopsy Breast Imaging Reporting and Data System (BI-RADS) 4 and 5 lesions <2 cm in depth in 11 patients. Results indicate that sensitivity and spatial resolution are sufficient to image vessels as small as 0.2 mm in diameter at depths of ~15 mm in the human breast. Challenges observed include motion artifacts, as well as limited depth of field and sensitivity, which could be improved by correction algorithms and improved transducer technologies.

Normal Palmar Anatomy and Variations That Impact Median Nerve Decompression.

Annually, carpal tunnel release is one of the most commonly executed orthopaedic procedures. Despite the frequency of the procedure, complications may occur as a result of anatomic variations. Understanding both normal and variant anatomy, including anomalies in neural, vascular, tendinous, and muscular structures about the carpal tunnel, is fundamental to achieving both safe and efficacious surgery. Reviewing and aggregating this information reveals certain principles that may lead to the safest possible surgical approach. Although it is likely that no true internervous plane or so-called safe zone exists during the approach for carpal tunnel release, the long-ring web space axis does appear to pose the lowest risk to important structures.

Sonographic Findings of the Bifid Median Nerve and Persistent Median Artery in Carpal Tunnel: A Preliminary Study in Chinese Individuals

OBJECTIVE: The aim of this study was to investigate the prevalence of anatomic variations of the bifid median nerve, persistent median artery and persistent median vein in Chinese individuals and their relationship with carpal tunnel syndrome. METHODS: One hundred and sixty median nerves were examined using ultrasonography and colour Doppler ultrasonography. The location, shape, and size of the bifid median nerve, persistent median artery and persistent median vein were recorded. The cross-sectional area of the bifid median nerve (two trunks) was measured at the level of the pisiform. RESULTS: Among the 160 wrists examined, a bifid median nerve was observed in 15 (9.4%) wrists, and a persistent median artery was observed in 12 (7.5%) wrists. These two variations either coexisted or were observed independently, and the probability of coexistence (6.3%) was higher than the probability of existing independently (bifid median nerve only 3.1%, persistent median artery only 1.3%). The cross-sectional area of the radial trunk was greater than (13 in 15, 86.7%) the cross-sectional area of the ulnaris trunk. Persistent median vein was observed in 9 wrists (5.6%). CONCLUSIONS: The persistent median artery and bifid median nerve tend to coexist, and the persistent median vein sometimes runs parallel to the persistent median artery. Their positional relationship in carpal tunnel is uncertain, and thus, preoperative ultrasound is necessary. These three variations do not present any additional risk for the development of carpal tunnel syndrome.

Anatomic Anomalies Encountered in 467 Open Carpal Tunnel Surgeries.

Carpal tunnel syndrome is the most common compression neuropathy and carpal tunnel surgery is the most frequently performed hand surgery. Anatomic anomalies may predispose the median nerve to compression. The aim of the current study was to search for anatomic anomalies in open carpal tunnel surgeries through a cross-sectional study. During a cross-sectional study in a one-year period, 436 consecutive patients (307 females and 129 males) with the average age of 50.3 ± 2.4 years underwent 467 classic open carpal tunnel surgeries. Thirty-one patients had bilateral surgeries. A thorough inspection of the incisions was conducted to search for vascular, neural, tendon and muscular anomalies. Forty-two (8.9%) hands (14 males and 28 females) had anomalies. The average age of the patients with discovered anomalies was 48.6 ± 7.6 years. Ten anomalies were seen on the left hands and 32 anomalies were seen on the right hands. Among the 42 anomalies, there were 16 persistent median arteries, 14 anomalies of the median nerve, 7 intratunnel intrusion of the flexor and lumbrical muscle bellies and 5 anomalies of the origin of the thenar muscles. There was no correlation between the discovered anomalies and the age, gender or hand sides. Anatomical anomalies are not uncommon in carpal tunnel surgeries. However, the frequencies of the reported anomalies vary among different studies. Familiarity with these anomalies increases the safety of the operation.