Use of the Humeral Head as a Reference Point to Prevent Axillary Nerve Damage during Proximal Fixation of Humeral Fractures: An Anatomical and Radiographic Study.

INTRODUCTION: Treatment of proximal humeral fractures with plate osteosynthesis or intramedullary nail fixation in humeral shaft fractures with a proximal locking bolt carries the risk of iatrogenic injury of the axillary nerve. The purpose of this anatomical study is to define a more reliable safe zone to prevent iatrogenic axillary nerve injury using the humeral head instead of the acromion as a (radiographic) reference point during operative treatment. MATERIALS AND METHODS: Anatomical dissection and labeling of the axillary nerve and branches was performed on 10 specially embalmed human specimens. Standard AP and straight lateral radiographs were made. The distances were measured indirectly from the cranial tip of the humerus to the axillary nerve on radiographs. RESULTS: The median distance from the cranial tip of the humerus to the axillary nerve was 52 mm. The mean number of axillary nerve branches was 3. The distances from the cranial tip of the humerus to the nerve (branch) varied from 23 to 78 mm. The median distance from the proximal (anterior) branch was 36 mm, to the second branch 47 mm, 54 mm to the third branch and 73 mm to the fourth branch. The axillary nerve moves along with the humerus in cranial and caudal direction when the subacromial space varies. CONCLUSION: This study shows that the position of the axillary nerve can be better determent using the cranial tip of the humerus as a reference point instead of the acromion. Furthermore, it is unsafe to place the proximal locking bolts in the zone between 24 mm and 78 mm from the cranial tip of the humerus. The greatest chance to cause a lesion of the main branch of the axillary nerve is in the zone between 48 mm and 58 mm caudal from the tip of the humeral head. HOW TO CITE THIS ARTICLE: Theeuwes HP, Potters JW, Bessems JHJM, et al. Use of the Humeral Head as a Reference Point to Prevent Axillary Nerve Damage during Proximal Fixation of Humeral Fractures: An Anatomical and Radiographic Study. Strategies Trauma Limb Reconstr 2020;15(2):63-68.

The course of the radial nerve in the distal humerus: A novel, anatomy based, radiographic assessment.

METHODS AND FINDINGS: Measurements were done on both arms of ten specially embalmed specimens. Arms were dissected and radiopaque wires attached to the radial nerve in the distal part of the upper arm. Digital radiographs were obtained to determine the course of the radial nerve in the distal 20 cm of the humerus in relation to bony landmarks; medial epicondyle and capitellum-trochlea projection (CCT). Analysis was done with ImageJ and Microsoft Excel software. We also compared humeral nail specifications from different companies with the course of the radial nerve to predict possible radial nerve damage. RESULTS: The distance from the medial epicondyle to point where the radial nerve bends from posterior to lateral was 142 mm on AP radiographs and 152 mm measured on the lateral radiographs. The average distance from the medial epicondyle to point where the radial nerve bends from lateral to anterior on AP radiographs was 66 mm. On the lateral radiographs where the nerve moves away from the anterior cortex 83 mm to the center of capitellum and trochlea (CCT). The distance from the bifurcation of the radial nerve into the posterior interosseous nerve (PIN) and superficial radial nerve was 21 mm on AP radiographs and 42 mm on the lateral radiographs (CCT). CONCLUSIONS: The course of the radial nerve in the distal part of the upper arm has great variety. Lateral fixation is relatively safe in a zone between the center of capitellum-trochlea and 48 mm proximal to this point. The danger zone in lateral fixation is in-between 48-122 mm proximal from CCT. In anteroposterior direction; distal fixation is dangerous between 21-101 mm measured from the medial epicondyle. The more distal, the more medial the nerve courses making it more valuable to iatrogenic damage. The IMN we compared with our data all show potential risk in case of (blind) distal locking, especially from lateral to medial direction.

Anatomical study of the dorsal cutaneous branch of the ulnar nerve (DCBUN) and its clinical relevance in TFCC repair.

The aim of this study was to define a detailed description of the dorsal cutaneous branch of the ulnar nerve (DCBUN) in particular in relevance to triangular fibrocartilage complex (TFCC) repairs. In 20 formalin-embalmed arms, the DCBUN was dissected, and the course in each arm was mapped and categorized. Furthermore, the point of origin of the DCBUN, that is, from the ulnar nerve in association with the ulnar styloid process, was defined. Finally, the distance between the ulnar styloid process and the branching of the radial-ulnar communicating branch (RUCB) and the first branch of DCBUN was measured. The distance between the origin of the DCBUN in relation to the ulnar styloid process ranges from 55 to 111 mm (mean 87 mm; STD 14 mm). The distance between the ulnar styloid process and the RUCB ranges from 1 to 54 mm (mean 19 mm; STD 12 mm). Finally, the distance between the ulnar styloid process and the lateral distal branch shows a range of -6 to 28 mm (mean 10 mm; STD 9 mm). In general, three dorsal digital nerves (medial, intermediate, and lateral branch), run at the dorsal ulnar aspect of the hand. The RUCB is often less abundant and shows a large amount of variation. No complete safe zone could be identified; the course of the DCBUN suggests a longitudinal incision for the 6R portal. In fact, a more dorsal incision also prevents damage to the main branches of the DCBUN.

The anatomical relationship of the superficial radial nerve and the lateral antebrachial cutaneous nerve: A possible factor in persistent neuropathic pain.

The superficial branch of the radial nerve (SBRN) is known for developing neuropathic pain syndromes after trauma. These pain syndromes can be hard to treat due to the involvement of other nerves in the forearm. When a nerve is cut, the Schwann cells, and also other cells in the distal segment of the transected nerve, produce the nerve growth factor (NGF) in the entire distal segment. If two nerves overlap anatomically, similar to the lateral antebrachial cutaneous nerve (LACN) and SBRN, the increase in secretion of NGF, which is mediated by the injured nerve, results in binding to the high-affinity NGF receptor, tyrosine kinase A (TrkA). This in turn leads to possible sprouting and morphological changes of uninjured fibers, which ultimately causes neuropathic pain. The aim of this study was to map the level of overlap between the SBRN and LACN. Twenty arms (five left and 15 right) were thoroughly dissected. Using a new analysis tool called CASAM (Computer Assisted Surgical Anatomy Mapping), the course of the SBRN and LACN could be compared visually. The distance between both nerves was measured at 5-mm increments, and the number of times they intersected was documented. In 81% of measurements, the distance between the nerves was >10 mm, and in 49% the distance was even <5 mm. In 95% of the dissected arms, the SBRN and LACN intersected. On average, they intersected 2.25 times. The close (anatomical) relationship between the LACN and the SBRN can be seen as a factor in the explanation of persistent neuropathic pain in patients with traumatic or iatrogenic lesion of the SBRN or the LACN.

Innervation mapping of the hind paw of the rat using Evans Blue extravasation, Optical Surface Mapping and CASAM.

BACKGROUND: Although numerous studies investigate sensory regeneration and reinnervation of the hind paw of the rat after nerve damage, no comprehensive overview of its normal innervation is present in literature. The Evans Blue extravasation technique is a well-known technique to study patterns of skin innervation. This technique has been performed differently by various groups but was never used to study the entire skin innervation in rats' hind paw including all three branches of the sciatic nerve and the saphenous nerve in detail. NEW METHOD: In this paper, we have used the Evans Blue extravasation technique to chart the skin areas innervated by the sural, peroneal, tibial and/or saphenous nerves, which together innervate the entire hind paw of the rat, and use a new technique to analyze the distribution, overlap and variability of the results. The technique is based on analysis of whole hind paws using Optical Surface Mapping (OSM) in combination with the Computer Assisted Surgical Anatomy Mapping (CASAM) technology. RESULTS: While the plantar hind paw is mainly innervated by the tibial nerve, the dorsal hind paw is supplied by the sural, peroneal and the saphenous nerve. COMPARISON WITH EXISTING METHODS: Although our results basically concur with the general nerve-specific innervation of the rat hind paw, they show considerable detail in their areas of overlap as well as in the amount of variability between animals. CONCLUSION: These results will be invaluable to study and evaluate patterns of innervation and reinnervation of intact and damaged nerve fibers.

The surgical anatomy of the infrapatellar branch of the saphenous nerve in relation to incisions for anteromedial knee surgery.

BACKGROUND: Iatrogenic injury to the infrapatellar branch of the saphenous nerve is a common complication of surgical approaches to the anteromedial side of the knee. A detailed description of the relative anatomic course of the nerve is important to define clinical guidelines and minimize iatrogenic damage during anterior knee surgery. METHODS: In twenty embalmed knees, the infrapatellar branch of the saphenous nerve was dissected. With use of a computer-assisted surgical anatomy mapping tool, safe and risk zones, as well as the location-dependent direction of the nerve, were calculated. RESULTS: The location of the infrapatellar branch of the saphenous nerve is highly variable, and no definite safe zone could be identified. The infrapatellar branch runs in neither a purely horizontal nor a vertical course. The course of the branch is location-dependent. Medially, it runs a nearly vertical course; medial to the patellar tendon, it has a -45° distal-lateral course; and on the patella and patellar tendon, it runs a close to horizontal-lateral course. Three low risk zones for iatrogenic nerve injury were identified: one is on the medial side of the knee, at the level of the tibial tuberosity, where a -45° oblique incision is least prone to damage the nerves, and two zones are located medial to the patellar apex (cranial and caudal), where close to horizontal incisions are least prone to damage the nerves. CONCLUSIONS: The infrapatellar branch of the saphenous nerve is at risk for iatrogenic damage in anteromedial knee surgery, especially when longitudinal incisions are made. There are three low risk zones for a safer anterior approach to the knee. The direction of the infrapatellar branch of the saphenous nerve is location-dependent. To minimize iatrogenic damage to the nerve, the direction of incisions should be parallel to the direction of the nerve when technically possible. CLINICAL RELEVANCE: These findings suggest that iatrogenic damage of the infrapatellar branch of the saphenous nerve can be minimized in anteromedial knee surgery when both the location and the location-dependent direction of the nerve are considered when making the skin incision.

An anatomical study of the ECRL and ECRB: feasibility of developing a preoperative test for evaluating the strength of the individual wrist extensors.

BACKGROUND: Tendon transfers are essential for reconstruction of hand function in tetraplegic patients. To transfer the extensor carpi radialis longus (ECRL), the extensor carpi radialis brevis (ECRB) has to be sufficiently strong. However, there is currently no reliable clinical test to individually analyse both muscles. In order to develop a reliable preoperative clinical test, the anatomy of the muscle (innervation) areas of ECRB, ECRL and brachio-radialis (BR) was examined. METHODS: In 20 arms, the ECRB, ECRL and BR were dissected and localised. Subsequently, muscle-innervation points were mapped and categorised. A novel method, computer-assisted surgical anatomy mapping (CASAM), was used to visualise muscle areas and innervation points in a computed arm with average dimensions. RESULTS: For both ECRL and ECRB a 100% area could be identified, a specific area in the computed average arm in which the muscle was present for all 20 arms. For the ECRL, this area was situated at 16% of the distance between the lateral epicondyle and the deltoid muscle insertion. The ECRB 100% area was 5 times bigger than that of the ECRL and was located at 40% of the distance between the lateral epicondyle and the radial styloid process. The ECRL and BR showed one to three innervation points, the ECRB one to four. In 47% of the cases, there was a combined nerve branch innervating both the ECRL and the ECRB. CONCLUSIONS: It is feasible to develop a preoperative test; the 100% areas can be used for needle electromyography (EMG) or local anaesthetic muscle injections.

Perforating veins: an anatomical approach to arteriovenous fistula performance in the forearm.

OBJECTIVES: Arteriovenous fistulae (AVFs) play a key role for people who rely on chronic haemodialysis. Stenosis in the venous outflow of the AVF will cause an alternative route of the subcutaneous blood flow via the deeper venous pathways by means of side branches and the perforating veins (PVs). The purpose for the present study was to define the number and anatomical localisation of the perforating veins in the forearm. METHODS: Twenty forearms were dissected to study the venous anatomy. The localisation, size and connections of the perforators were recorded and stored digitally. RESULTS: In total, 189 PVs were defined (mean, 9.5 per arm; range, 6-19), with 60 (32%) PVs connected to the cephalic vein, 97 (51%) connections to the basilic vein and 32 (17%) PVs to the median vein of the forearm. Most PVs originate from the basilic vein and connect with the ulnar venae comitans. The cephalic vein connects equally to the radial venae comitans, interossea veins and the muscles. CONCLUSION: The cephalic vein has the fewest PVs and almost a third of them connect to the muscles. This is probably important for the maturation of the AVF, the superficial flow volume and the accessibility for puncture.

[Transoral endoscopic thyroidectomy. Part 1: rationale and anatomical studies]. / Transorale endoskopische Thyreoidektomie: Teil 1: Rationale und anatomische Studien.

BACKGROUND: Surgical access trauma in thyroidectomy has been minimized by the adoption of minimally invasive techniques. Extracervical approaches moved the incision lines outside of the visible neck region. However, because of the extensive dissection they no longer comply with the term minimally invasive. Therefore, our goal was to reduce the access trauma and establish a non-traumatic approach according to surgical planes for endoscopic minimally invasive thyroidectomy: the transoral approach. MATERIAL AND METHODS: In a preclinical investigation anatomical dissection was performed on three human cadavers to visualize anatomical relationships and identify safe zones of access to the anterior neck and the submandibular regions. The investigation focused on relevant vascular and neural structures in the floor of mouth. Endoscopic minimally invasive thyroidectomy was additionally performed in five specimens with anatomical dissections for the evaluation of collateral damage. RESULTS: For a safe approach the optic trocar can be placed sublingually in the midline as there are no relevant vascular or neural structures on the way to the thyroid region. The working trocars can be placed bilaterally in the oral vestibule behind the canine teeth. In this way access and dissection plane are placed directly in an avascular subplatysmal area and the pretracheal working space can be reached easily, safe and fast. CONCLUSIONS: Minimum impact and a gentle dissection according to anatomical planes are the rational for the transoral route to the thyroid gland. Thus based on anatomical dissections the foundations of a novel procedure in the context of natural orifice surgery (NOS) could be established.

[Transoral endoscopic thyroidectomy : Part 2: Surgical technique]. / Transorale endoskopische Thyreoidektomie : Teil 2: Operationstechnik.

BACKGROUND: Thyroid surgery is one of the newest fields for application of video-assisted surgery. The majority of approaches must choose between optimizing cosmetic results by hiding scars in the chest and axillary region while maximizing tissue dissection and post-operative pain versus having a visible cervical scar with minimal tissue dissection. In an effort to minimize surgical trauma and to achieve an optimal cosmetic result we investigated the transoral approach to the thyroid. MATERIAL AND METHODS: In three cadavers the safety and reproducibility to access and resect the thyroid gland were assessed according to a defined road map. The surgical procedure itself was performed on two further cadavers with the help of one 5 mm trocar and two 3 mm trocars which were introduced bilaterally through the floor of mouth and the oral vestibule. A subplatysmal working space was created by blunt dissection and CO(2) insufflation to a pressure of 4-6 mmHg. Division of the median raphe of the neck muscles was followed by exposure of the thyroid gland. In the next step the isthmus was transected, the upper pole arteries dissected and divided and the medial thyroid vein cut close to the gland. Thyroid resection was performed from cranial to caudal and the specimen was removed transorally through the 5 mm midline incision. RESULTS: Description of landmarks of the surgical steps and dissection of defined anatomic structures could be achieved. Unilateral subtotal thyroid resection could be successfully performed without any additional skin incisions in 59 min. Postoperatively performed anatomical dissection showed intact surrounding structures. CONCLUSION: Our results demonstrate the feasibility and safety of a transoral access for thyroidectomy. In comparison to other minimally invasive thyroidectomy access procedures, the transoral approach is minimally invasive and at the same time cosmetically optimal.

Treatment of unstable trochanteric fractures. Randomised comparison of the gamma nail and the proximal femoral nail.

The proximal femoral nail (PFN) is a recently introduced intramedullary system, designed to improve treatment of unstable trochanteric fractures of the hip. In a multicentre prospective clinical study, the intra-operative use, complications and outcome of treatment using the PFN (n = 211) were compared with those using the gamma nail (GN) (n = 213). The intra-operative blood loss was lower with the PFN (220 ml v 287 ml, p = 0.001). Post-operatively, more lateral protrusion of the hip screws of the PFN (7.6%) was documented, compared with the gamma nail (1.6%, p = 0.02). Most local complications were related to suboptimal reduction of the fracture and/or positioning of the implant. Functional outcome and consolidation were equal for both implants. Generally, the results of treatment of unstable trochanteric fractures were comparable for the PFN and GN. The pitfalls and complications were similar, and mainly surgeon- or fracture-related, rather than implant-related.

Prevention of colonization and infection in critically ill patients: a prospective randomized study.

In a prospective randomized study to determine whether prevention of colonization of Gram-negative bacteria results in prevention of Gram-negative bacterial infections, 96 intensive care patients were randomly allocated into a control group and a study group. The study group received oral nonabsorbable antimicrobial agents (i.e., tobramycin, amphotericin B, and polymyxin E) in addition to parenteral antibiotics. Colonization with Gram-negative microorganisms in the oropharynx, and respiratory and digestive tracts increased in the control group during their stay, while the study group did not tend to colonize with Gram-negative bacteria. In the control group, 107 nosocomial infections were diagnosed, vs. 42 nosocomial infections in the study group. Nosocomial infections caused by Gram-negative bacteria were significantly less frequent in the study group. Mortality due to an acquired infection was significantly less frequent in the study group. We conclude that colonization, infection, and subsequent mortality by nosocomial Gram-negative bacteria can be prevented by a regime of topically applied nonabsorbable antibiotics.

Endemic Acinetobacter anitratus in a surgical intensive care unit: mechanical ventilators as reservoir.

Colonization and infection with an endemic multiresistant strain of Acinetobacter calcoaceticus variety anitratus had been observed in the surgical intensive care unit of a university hospital since 1982. An outbreak of infection with this endemic, multiresistant Acinetobacter anitratus strain occurred between January and September, 1984. After initial attempts at identification of environmental reservoirs had been unsuccessful, risk factors for the acquisition of Acinetobacter anitratus were investigated by comparing the epidemiological characteristics of patients who became colonized or infected with those of control patients without colonization. The results of this case-control study and of the ensuing specific cultures indicated that ventilators in use in the unit were the reservoirs of Acinetobacter anitratus, resulting in frequent nosocomial respiratory tract infections. After modification of the mechanical ventilators, colonization and infection rates with Acinetobacter anitratus decreased. Since January 1985, no new cases of colonization or infection with this endemic strain of Acinetobacter anitratus have been recorded.

Colonization and infection in surgical intensive care patients--a prospective study.

Nosocomial infections are a major problem in intensive care patients. Thirty-nine patients, requiring intensive care for 5 days or more (mean 15.8 days) were prospectively investigated, to determine the relation between colonisation and nosocomial infection. Thrice weekly, cultures from the oropharynx, respiratory and digestive tract were obtained. Colonization with aerobic gram-negative microorganisms of the oropharynx, respiratory and digestive tract significantly increased during the stay in the Intensive Care Unit. In 29 patients (74%) 78 nosocomial infections were diagnosed. The most frequent nosocomial infections were pneumonia (26 patients, 66.6%), catheter-related bacteraemia (11 patients, 28.2%), and wound infections (7 patients, 17.9%). In 59 instances (75.6%), colonization with the same potential pathogenic microorganism preceded the nosocomial infection. The overall mortality was 25.6% (10 patients), bacteraemia with aerobic gram-negative microorganisms being the cause of death in 7 patients.