Anatomical quantitative evaluation of popliteal artery visualization during medial approach in supine position.

PURPOSE: The medial approach to the popliteal artery has been less commonly used than the posterior approach in surgical repair of traumatic popliteal injury. This study was performed to quantitatively evaluate the visual field of the popliteal artery obtained by staged myotendotomy in the medial approach to the popliteal artery. METHODS: Twenty legs of fresh-frozen adult cadavers were dissected using the medial approach to the popliteal artery. In stage 1, the popliteal artery was exposed between the vastus medialis and sartorius muscles without myotendotomy. In stage 2, the medial head of the gastrocnemius muscle was dissected. In stage 3, the tendons of the sartorius and semimembranosus muscles were dissected. In stage 4, the tendons of the gracilis and semitendinosus muscles were dissected to fully expose the popliteal artery. The length of the popliteal artery that could be visualized in each stage was measured. RESULTS: The anatomical length of the popliteal artery from the hiatus of the adductor magnus to the tendinous arch of soleus muscle ranged from 15 to 20 cm (mean, 16.3 cm). On average, 45%, 59%, 72%, and 100% of the popliteal artery were visualized in stage 1, 2, 3, and 4, respectively. CONCLUSIONS: The medial approach to the popliteal artery has the advantage of being performed in the supine position, but it requires multiple myotendotomies around the knee. The results of this study may serve as a reference for myotendotomy depending on the site of injury to the popliteal artery.

Template-based target point localization for occlusion of the middle meningeal artery during evacuation of space-occupying chronic subdural hematoma.

OBJECTIVE: Endovascular middle meningeal artery (MMA) occlusion may help reduce the risk of recurrence after burr hole evacuation of chronic subdural hematoma (cSDH) but carries an additional periprocedural risk and remains hampered by logistical and financial requirements. In this study, the authors aimed to describe a simple and fast technique for preoperative MMA localization to permit burr hole cSDH evacuation and MMA occlusion through the same burr hole. METHODS: The authors performed a preclinical anatomical and prospective clinical study, followed by a retrospective feasibility analysis. An anatomical cadaver study with 33 adult human skulls (66 hemispheres) was used to localize a suitable frontal target point above the pterion, where the MMA can be accessed via burr hole trephination. Based on anatomical landmark measurements, the authors designed a template for projected localization of this target point onto the skin. Next, the validity of the template was tested using image guidance in 10 consecutive patients undergoing elective pterional craniotomy, and the feasibility of the target point localization for cSDH accessibility was determined based on hematoma localization in 237 patients who were treated for a space-occupying cSDH in the authors' department between 2014 and 2018. RESULTS: In the anatomical study, the mean perpendicular distance from the zygomatic process to the target point in the frontoparietal bone was 4.1 cm (95% CI 4-4.2 cm). The mean length along the upper margin of the zygomatic process from the middle of the external auditory canal to the point of the perpendicular distance was 2.3 cm (95% CI 2.2-2.4 cm). The template designed according to these measurements yielded high agreement between the template-based target point and the proximal MMA groove inside the frontoparietal bone (right 90.9%; left 93.6%). In the clinical validation, we noted a mean distance of 4 mm (95% CI 2.1-5.9 mm) from the template-based target point to the actual MMA localization. The feasibility analysis yielded that 95% of all cSDHs in this cohort would have been accessible by the new frontal burr hole localization. CONCLUSIONS: A template-based target point approach for MMA localization may serve as a simple, fast, reliable, and cost-effective technique for surgical evacuation of space-occupying cSDHs with MMA obliteration through the same burr hole in a single setting.

Minimally invasive cerclage at the tibia using a modified Goetze technique: An anatomical study.

INTRODUCTION: The use of minimally invasive cerclages at the tibia is not very common. First, clinical results of a new operative technique published recently showed no increased complication rate. The aim of this anatomical study was to determine, if it is possible to introduce a minimally invasive cerclage at different levels of the tibia without encasing relevant nerves, vessels or tendons into the cerclage using this technique. HYPOTHESIS: The minimally invasive introduction of a cerclage at the tibia is possible without encasing relevant anatomical structures. MATERIAL AND METHODS: Using the minimally invasive operative technique in 10 human cadaveric lower legs, cerclages were inserted at 4 different levels of each tibia. They were defined from proximal to distal as level 1-4. The legs were severed at the levels of the cerclages and examined for any relevant encased anatomical structures. Afterwards, the shortest distance between each relevant anatomical structure and the cerclage was measured. RESULTS: There was no encasing of any relevant anatomical structures in any specimen at any level. In the proximal half of the lower leg, the closest anatomical structures to the inserted cerclage were arteria et vena tibialis posterior (at level 1: 5.2 resp. 4.3mm, at level 2: 4.0 resp. 5.5mm). In the distal half of the lower leg arteria et vena tibialis anterior (level 3: 1.8 and 2.0mm, level 4: 1.6 and 1.5mm), nervus fibularis profundus (level 3: 2.2mm, level 4: 1.2mm) and the tendon of musculus tibialis posterior (level 3: 0.8mm, level 4: 1.1mm) were in closest proximity of the cerclage. DISCUSSION: The results of this anatomical study suggest that the minimally invasive insertion of cerclages at the tibia without encasing relevant anatomical structures is possible but requires a correct operative technique. The structures at highest risk are arteria et vena tibialis posterior in the proximal half of the tibia and arteria et vena tibialis anterior, nervus fibularis profundus and the tendon of musculus tibialis posterior in the distal half. LEVEL OF EVIDENCE: Not applicable; experimental anatomical study.

Supraorbital Keyhole Versus Pterional Approach: A Morphometric Anatomical Study.

OBJECTIVE: Although the supraorbital (SO) keyhole approach has a wide range of indications, its routine usefulness with the advance of current technology has not been fully evaluated. In an attempt to address this issue, a cadaveric morphometric analysis to the supra- and parasellar regions was performed, comparing the standard Pterional craniotomy (PT) with the SO keyhole. METHODS: ETOH-fixed and silicone-injected human cadaveric heads were used. SO (n = 8) and PT craniotomies (n = 8) were performed. Pre- and post-dissection CT, along with pre-dissection MRI scans were also completed for neuro-navigation purposes, aimed to verify predetermined anatomical landmarks selected for morphometric analysis. RESULTS: Notwithstanding the smaller craniotomy, the SO approach allowed optimal anatomical exposure when compared to the PT approach. With 30° of head rotation, the SO keyhole showed a wider surgical field of the suprasellar region. CONCLUSIONS: Using detailed preoperative image-guided surgical planning, the SO keyhole approach offered an appropriate alternative route to the supra- and parasellar regions, compared to the PT craniotomy.

Implantation of Surgical Paddle Electrodes Using Percutaneous Biportal-Endoscopic Technique for Spinal Cord Stimulation: An Anatomical Feasibility Study in Human Cadavers.

BACKGROUND: Spinal cord stimulation is a technique in which different types of electrodes are placed in the spinal epidural space for neuromodulation. Surgical paddle electrodes (SEs) are usually implanted by a surgeon by performing open surgery with laminectomy. Recent advances in endoscopic spine surgery provide another option for minimally invasive SE implantation. OBJECTIVES: This anatomical study aims to examine the feasibility of implanting SEs in thoracic and cervical spine segments, discussing the specific advantages and disadvantages compared with previously reported methods. STUDY DESIGN: Laboratory study with Institutional Review Board No B2023-056. METHODS: Four fresh adult cadavers (2 women, 2 men) were operated on in this study. The posterior unilateral biportal endoscopic surgical approach, the accessibility to the intraspinal epidural space, and the technical possibilities and limitations of implantation of SEs were evaluated, as well as the surgical duration and complications. RESULTS: All the planned steps of the operation were successfully accomplished in all 4 cadavers. A total of 8 electrodes were successfully implanted through the working portal. Among them, 4 were located in the cervical segment and 4 in the thoracic segment. The proper position of the electrodes was also verified by fluoroscopy. No rupture of dura occurred during the operation. Except for the first cadaver, the duration of surgery did not exceed 1 hour. LIMITATIONS: Anatomical study on human cadavers, the quantity of cadavers, and the steep learning curve. CONCLUSIONS: The results of this anatomical study show that the SEs can be satisfactorily implanted in cervical and thoracic segments using the unilateral biportal endoscopic technique.

Restoration of intrinsic hand function by superficial radial nerve: an anatomical study.

BACKGROUND: The contralateral seventh cervical (cC7) nerve root transfer represents a cornerstone technique in treating total brachial plexus avulsion injury. Traditional cC7 procedures employ the entire ulnar nerve as a graft, which inevitably compromises its restorative capacity. OBJECTIVE: Our cadaveric study seeks to assess this innovative approach aimed at preserving the motor branch of the ulnar nerve (MBUN). This new method aims to enable future repair stages, using the superficial radial nerve (SRN) as a bridge connecting cC7 and MBUN. METHODS: We undertook a comprehensive dissection of ten adult cadavers, generously provided by the Department of Anatomy, Histology, and Embryology at Fudan University, China. It allowed us to evaluate the feasibility of our proposed technique. For this study, we harvested only the dorsal and superficial branches of the ulnar nerve, as well as the SRN, to establish connections between the cC7 nerve and recipient nerves (both the median nerve and MBUN). We meticulously dissected the SRN and the motor and sensory branches of the ulnar nerve. Measurements were made from the reverse point of the SRN to the wrist flexion crease and the coaptation point of the SRN and MBUN. Additionally, we traced the MBUN from distal to proximal ends, recording its maximum length. We also measured the diameters of the nerve branches and tallied the number of axons. RESULTS: Our modified approach proved technically viable in all examined limbs. The distances from the reverse point of the SRN to the wrist flexion crease were 8.24 ± 1.80 cm and to the coaptation point were 6.60 ± 1.75 cm. The maximum length of the MBUN was 7.62 ± 1.03 cm. The average axon diameters in the MBUN and the anterior and posterior branches of the SRN were 1.88 ± 0.42 mm、1.56 ± 0.38 mm、2.02 ± 0.41 mm,respectively. The corresponding mean numbers of axons were 1426.60 ± 331.39 and 721.50 ± 138.22, and 741.90 ± 171.34, respectively. CONCLUSION: The SRN demonstrated the potential to be transferred to the MBUN without necessitating a nerve graft. A potential advantage of this modification is preserving the MBUN's recovery potential.

The feasibility of a new self-guided pedicle tap for pedicle screw placement: an anatomical study.

PURPOSE: To investigate the safety and accuracy of applying a new self-guided pedicle tap to assist pedicle screw placement. METHODS: A new self-guided pedicle tap was developed based on the anatomical and biomechanical characteristics of the pedicle. Eight adult spine specimens, four males and four females, were selected and tapped on the left and right sides of each pair of T1-L5 segments using conventional taps (control group) and new self-guided pedicle taps (experimental group), respectively, and pedicle screws were inserted. The screw placement time of the two groups were recorded and compared using a stopwatch. The safety and accuracy of screw placement were observed by CT scanning of the spine specimens and their imaging results were graded according to the Heary grading criteria. RESULTS: Screw placement time of the experimental group were (5. 73 ± 1. 18) min in thoracic vertebrae and (5. 09 ± 1. 31) min in lumbar vertebrae respectively. Screw placement time of the control group were respectively (6. 02 ± 1. 54) min in thoracic vertebrae and (5.51 ± 1.42) min in lumbar vertebrae. The difference between the two groups was not statistically significant (P > 0. 05). The Heary grading of pedicle screws showed 112 (82.35%) Heary grade I screws and 126 (92.65%) Heary grade I + II screws in the experimental group, while 96 (70.59%) Heary grade I screws and 112 (82.35%) Heary grade I + II screws in the control group.The difference between the two groups was statistically significant (P < 0.05). CONCLUSION: The new self-guided pedicle tap can safely and accurately place thoracic and lumbar pedicle screws with low-cost and convenient procedure,which indicates a good clinical application value.

Anatomical Study of the Nerve Supply of the Dromedary Camel (Camelus dromedarius) in the Distal Hindlimb with a Special Reference to the Cutaneous Innervation.

This study aimed to describe the anatomy of the nerve supply of the hindlimb's distal portion in a dromedary camel's foot. In our study, we used ten adult slaughtered dromedary camels (twenty distal hindlimbs) of different sexes and ages (4-6 years). The hindlimbs were preserved using 10% formalin for about one week. The distal part of the hindlimb of the camels was dissected with extreme precision to show the group of nerves responsible for the nervous supply to the distal part of the hindlimb in dromedary camels. This study shows the numerous branches of the superficial fibular nerve along its extension to the dorsal surface metatarsus and the abaxial aspect of the third digit. The results show that the tibial nerve possesses many branches along its extension to the plantar surface skin of the metatarsus. Additionally, it provides the axial and abaxial plantar surfaces of the fourth digit and the interdigital surfaces as well as its branches to supply the plantar-abaxial and plantar-axial of the third digit. The present study shows the anatomical nerve supply of the hindlimb's distal portion that is essential for anesthesia and surgery in this region.

Anatomic Study of the Motor Branch of the Ulnar Nerve Regarding Carpal Tunnel Surgery: A Cadaveric Study.

Background: Motor branch of the ulnar nerve (MUN) injury during carpal tunnel surgery is rare and it should never be injured during carpal tunnel release (CTR). However, an iatrogenic injury of the MUN can cause catastrophic physical and mental suffering. The aim of our study is to understand the anatomy of the MUN in relation to carpal tunnel in order to prevent iatrogenic injury during CTR. Methods: We dissected 34 fresh cadaver hands and located the MUN in relation to the anatomical axis used for carpal tunnel surgery. Possible mechanisms of injury and the vulnerable area of the MUN were determined along the dissection. Results: The MUN turned towards the thumb distal to hook of hamate. It then travelled on the floor of the carpal tunnel which was formed by intrinsic hand muscles under flexor tendons. The nerve located at 29.39 ± 7.41, 35.01 ± 3.14 and 38.79 ± 4.03 mm (Mean ± SD) in the central axis of ring finger, the vertical axis of the third web-space and the central axis of middle finger respectively. The nerve's turning point, 10.9 ± 2.63 mm distal to the centre of hook of hamate where it lies just below the level of the transverse carpal ligament. Conclusions: Surgeons should be aware of the nerve's location. Surgical dissection or passing of any surgical instruments around the hook of hamate should be done with care. Level of Evidence: Level IV (Therapeutic).

Rat Perforator and Skin Vessels Vascular Mapping: An Original Anatomical Study About 140 Vessels and Literature Review.

INTRODUCTION: Recent microsurgical reconstruction techniques benefit from the use of skin and perforator flaps that spare the donor sites. Studies on these skin flaps in rat models are numerous but there is currently no reference regarding the position of the perforators, their caliber, and the length of the vascular pedicles. METHODS: We performed an anatomical study on 10 Wistar rats and 140 vessels: cranial epigastric (CE), superficial inferior epigastric (SIE), lateral thoracic (LT), posterior thigh (PT), deep iliac circumflex (DCI) and posterior intercostal (PIC) vessels. The evaluation criteria were the external caliber, the length of the pedicle, and the position of the vessels reported on the skin surface. RESULTS: Data from the six perforator vascular pedicles are reported, with figures illustrating the orthonormal reference frame, the representation of the vessel's position, the cloud of points corresponding to the various measurements, and the average representation of the collected data. The analysis of the literature does not find similar studies; the different vascular pedicles are discussed as well as the limitations of our study: evaluation of cadaver specimen, presence of the very mobile panniculus carnosus, other perforator vessels not evaluated as well as the precise definition of perforating vessels. CONCLUSIONS: Our work describes the vascular calibers, pedicle lengths, and location of birth and arrival at the skin of the perforator vessels PT, DCI, PIC, LT, SIE, and CE in rat animal models. This work, without an equivalent in the literature, lays the foundation for future studies about flap perfusion, microsurgery, and super microsurgery learning.

Submental island flap - should we be worried about lymph node transfer? An anatomical and histological study.

The submental island flap has been increasing in popularity for both oncological and non-oncological reconstruction of the head and neck. However, the original description of this flap left it with the unfortunate designation as a lymph node flap. There has thus been significant debate on the oncological safety of the flap. In this cadaveric study the perforator system suppling the skin island is delineated and the lymph node yield of the skeletonised flap is analysed histologically. A safe and consistent approach to raising the perforator flap modification is described and the pertinent anatomy, and an oncological discussion with regards to the submental island perforator flap histological lymph node yield discussed. Ethical approval was received from Hull York Medical School for the anatomical dissection of 15 sides of cadavers. 6 x 4cm submental island flaps were raised following a vascular infusion of a 50/50 mix of acrylic paint. The flap size mimics the T1/T2 tumour defects these flaps would usually be used to reconstruct.The submental vascular anatomy, including length, diameter, venous drainage patterns, and the skin perforator system was documented. The dissected submental flaps were then histologically examined for the presence of lymph nodes by a head and neck pathologist at Hull University Hospitals Trust department of histology. The total length of the submental island arterial system, the distance from where the facial artery branches off from the carotid to the submental artery perforator entering the anterior belly of digastric or skin, averaged 91.1mm with anaverage facial artery length of 33.1mm and submental artery of 58mm. Vessel diameter for microvascular reconstruction was 1.63mm for the submental artery and 3mm for the facial artery. The most common venous anatomy drainage pattern was the submental island venaecomitantes draining to the retromandibular system then to the internal jugular vein. Almost half the specimens had a dominant superficial submental perforator allowing the ability to raise this as a skin only system. There were generally 2-4 perforators passing through the anterior belly of digastric to supply the skin paddle.73.3% (11/15) of the skeletonised flaps contained no lymph nodes on histological examination. The perforator version of the submental island flap can be safely and consistently raised with inclusion of the anterior belly of digastric. In approximately half the cases a dominant superficial branch allows for a skin only paddle. Due to the vessel diameter, free tissue transfer is predictable.Venous anatomy is variable and care needs to be taken when raising this flap. The skeletonised version of the perforator flap is largely devoid of nodal yield and on oncological review a 16.3% recurrence rate is equivalent to current standard treatment.

The placement of percutaneous retrograde acetabular posterior column screw based on imaging anatomical study of acetabular posterior column corridor.

OBJECTIVE: To explore the entry point, orientation, and fixation range of retrograde acetabular posterior column screw. METHOD: The computed tomography data of 100 normal adult pelvises (50 males and 50 females, respectively) were collected and pelvis three-dimensional (3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabular posterior column was carried out orienting from ischial tuberosity to iliac fossa in the Mimics software. Virtual screw was inserted perpendicular to the transverse section of acetabular posterior column corridor, and the maximum screw diameter, entry point, orientation, exit point were measured. The screw fixation range, the easy-to-penetrate sites, and intraoperative optimal fluoroscopic views were assessed. RESULTS: The acetabular posterior column corridor showed a triangular-prism shape. The virtual screw entry point was located at the midline between the medial and lateral edges of the ischial tuberosity. The distance between the entry point and the distal ischial tuberosity was around 13 mm. The distances between the exit point and the true pelvis rim, and ipsilateral anterior sacroiliac joint line were (19.33 ± 2.60) mm and (23.65 ± 2.42) mm in males, respectively. As for females, those two data were (17.63 ± 2.00) mm and (24.94 ± 2.39) mm, respectively. The maximum diameters of screws were (17.21 ± 1.41) mm in males and (15.54 ± 1.51) mm in females. The angle between the retrograde posterior column screw and the sagittal plane was lateral inclination (10.52 ± 3.04)° in males, and that was lateral inclination (7.72 ± 2.99)° in females. Correspondingly, the angle between the screw and the coronal plane was anterior inclination (15.00 ± 4.92)° in males, and that was anterior inclination (12.94 ± 4.72)° in females. Retrograde acetabular posterior column screw through ischial tuberosity can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center. The easy-to-penetrate sites were located at the transition between the posterior acetabular wall and the ischium, the middle of the acetabulum, and 1 cm below the greater sciatic notch, respectively. The iliac oblique 10°, iliac oblique 60°, and obturator oblique 60° views were the intraoperative optimal fluoroscopic views to assess whether the screw was safely inserted. CONCLUSION: Retrograde acetabular posterior column screw entry point is located at the midline between the medial and lateral edges of the ischial tuberosity, which is 1.3 cm far from the distal ischial tuberosity. The screw direction is about 10° lateral inclination and 15° anterior inclination, which can fix the acetabular posterior column fractures which were not 4 cm above the femoral head center.

Use of free radial forearm and pronator quadratus muscle flap: Anatomical study and clinical application.

The authors present an anatomical study and clinical experience with radial forearm flap (RFF) and pronator quadratus muscle (PQM) application in the reconstruction of various body areas. The aim was to describe the anatomical placement and proportions of the PQM, the anatomical location of the major arterial branch of the radial artery supplying the PQM, and the application of this knowledge in clinical practice. The anatomical study was based upon an analysis of 13 fresh adult cadaver upper extremities, of which nine were female and four male; both arms from the same donors were used in four cases. The study of the PQM was performed using a dye-containing intraarterial injection, standard macro- and micro-preparation techniques, and chemical digestion. The data on the PQM size in males and females, thickness of the radial artery branch (the principal artery nourishing the muscle), and its position were analysed. The radial artery branch nourishing the PQM was identified in all cadaveric specimens of the anatomical study. In addition, 12 patients underwent reconstructions of soft and bony tissue defects using a RFF + PQM (pedicled or free flap). The radial artery branch perfusing the PQM was identified in all cases. The flap was used for the management of defects of the head (seven cases), arm (three cases) and lower leg (two cases). The harvest site healed well in all cases and, with the exception of one case in which a partial necrosis of the flap was observed, all flaps remained viable, which demonstrated the safety of the method.

The sacrotuberous ligament is preloaded in situ.

The objective of this study was to evaluate the intrinsic preload of the sacrotuberous ligament. Preload measurements and anatomical experiments were performed on 20 specimens from 10 human cadavers and assessed to consider the thesis of the ligamentous tension band system as a possible load distribution. The result was an unexpectedly high preload force with an overall average of 118 N ± 74 N. Age has been significantly different between females and males in the cohort (median 94 vs. 77 years). Nevertheless, there is preliminary evidence of the sex-dependent sacrotuberous ligament preload force with an average value of approximately 65 N for the 10 female cadaver specimens and 172 N for the 10 male cadaver specimens. The assessment of further influencing factors and their statistical evaluation also showed a dependence of the sacrotuberous ligament preload force on body height, age and elastin content. Thus, the sacrotuberous ligament is more preloaded in the cadaver than previously assumed in the literature. Therefore, and contrary to most assumptions, it could possibly also be more preloaded in a living person in an upright position under a muscular load. This leads to the hypothesis that pelvic stability is more dependent on ligamentous preload than previously thought. These considerations should be taken more into account in numerical simulations of sacroiliac joint function.

Implant Sizing and Positioning in Anatomical Total Shoulder Arthroplasty Using a Rotator Cuff-Sparing Postero-Inferior Approach.

Background: The goal of this study was to compare the effectiveness of a rotator cuff-sparing postero-inferior (PI) approach with subdeltoidal access to the traditional subscapularis-takedown deltopectoral approach, in terms of implant sizing and positioning in anatomical total shoulder arthroplasty (aTSA). Methods: This study involved 18 human cadaveric shoulders with intact rotator cuffs and no evidence of head deforming osteoarthritis. An Eclipse stemless aTSA (Arthrex, Naples, FL, USA) was implanted in nine randomly selected specimens using a standard subscapularis-tenotomy deltopectoral approach, and in the other nine specimens using the cuff-sparing PI approach. Pre- and postoperative antero-posterior (AP) and axillary fluoroscopic radiographs were analyzed by two independent, blinded raters for the following parameters: (1) anatomic and prosthetic neck-shaft angle (NSA); (2) the shift between the anatomic and prosthetic center of rotation (COR); (3) anatomical size matching of the prosthetic humeral head; (4) the calculated Anatomic Reconstruction Score (ARS); (5) glenoid positioning; as well as (6) glenoid inclination and version. Results: While the COR was slightly but significantly positioned (p = 0.031) to be more medial in the PI approach group (3.7 ± 3.4%, range: -2.3% to 8.7%) than in the deltopectoral approach group (-0.2 ± 3.6%, range: -6.9% to 4.1%), on average, none of the remaining measured radiographic parameters significantly differed between both groups (PI approach group vs. deltopectoral group: NSA 130° vs. 127°, p = 0.57; COR supero-inferior, 2.6% vs. 1.0%, p = 0.35; COR antero-posterior, 0.9% vs. 1.7%, p = 0.57; head size supero-inferior, 97.3% vs. 98.5%, p = 0.15; head size antero-posterior, 101.1% vs. 100.6%, p = 0.54; ARS, 8.4 vs. 9.3, p = 0.13; glenoid positioning supero-inferior, 49.1% vs. 51.1%, p = 0.33; glenoid positioning antero-posterior, 49.3% vs. 50.4%, p = 0.23; glenoid inclination, 86° vs. 88°, p = 0.27; and glenoid retroversion, 91° vs. 89°, p = 0.27). Conclusions: A PI approach allows for sufficient exposure and orientation to perform rotator-cuff sparing aTSA with acceptable implant sizing and positioning in cadaveric specimens.

The Berrettini palmar neural communicating branch: a study of 27 cadaveric specimens and determination of a high-risk surgical zone.

In this cadaveric study, we analysed digital images of dissected palms to define the location and length of superficial connections between the median and the ulnar nerves (Berrettini communicating branches). We found the connections present in 12 of 27 hands. We used a coordinate model to define their location relative to seven specified landmarks. The model revealed that the Berrettini communicating branches were positioned consistently, and we defined a high-risk zone in the palm that fully contained seven of the 12 connections, while others had minor projections outside the zone. We conclude that awareness of this high-risk zone in the palm can be of some help to reduce the risk of iatrogenic nerve injury, however, any operation in the palm must always be done with great care to visualize and protect any possible anatomically unusual structures.

Ultrasound-Guided Percutaneous A1 Pulley Release by Acupotomy (Needle-Knife): A Cadaveric Study of Safety and Efficacy.

PURPOSE: This study was to assess the safety and effectiveness of ultrasound-guided percutaneous A1 pulley release by acupotomy on unembalmed cadavers. MATERIALS AND METHODS: Sixty digits (from six cadavers, three male and three female) were split into two groups using stratified randomization. All procedures were completed by a single doctor with rich experience in ultrasound-guided treatment. In the acupotomy group, the A1 pulley was released under ultrasound-guided by a needle-knife; while in the needle group, the A1 pulley was released under ultrasound-guided by a 21-gauge needle. Two groups completed six thumbs and 24 fingers, respectively. Another anatomist, blinded to the two techniques, assessed the safety, including the minimum distance between the incision and the neurovascular; flexor tendon, neurovascular and A2 pulley injury or not. Completeness release of the A1 pulley was recorded as effectiveness. RESULTS: No neurovascular or A2 pulley injuries were recorded. However, the incision of the thumb in both groups biased to the radial side (P <0.05), while the incision of the finger biased to the ulnar side (P <0.05). No significant flexor tendon injury was found, and only five cases (16.7%) had minor scratches in the acupotomy group; while in the needle group, 15 cases had minor scratches and lacerations occurred in three cases. The flexor tendon injury rate was 60%. Compared with the needle, ultrasound-guided acupotomy release is safer (P <0.05). The ultrasound-guided acupotomy technique was significantly more likely to result in a complete A1 pulley release compared to the needle technique (28 of 30 [93.3%] versus 11 of 30 [36.7%]; P <0.05). CONCLUSION: Ultrasound-guided percutaneous A1 pulley release by acupotomy is a safe and effective technique. When releasing the thumb by ultrasound-guided, be careful not to bias to the radial side to avoid neurovascular injury, while when releasing a finger, be careful not to bias to the ulnar side.

Anatomical relationship between the foramen ovale and the lateral plate of the pterygoid process: application to percutaneous treatments of trigeminal neuralgia.

Our aim was to clarify the variations in the positional relationship between the base of the lateral plate of the pterygoid process and the foramen ovale (FO), which block inserted needles during percutaneous procedures to the FO usually used for the treatment of trigeminal neuralgia. Ninety skulls were examined. The horizontal relationship between the FO and the posterior border of the base of the lateral plate of the pterygoid process was observed in an inferior view of the skull base. Skulls that showed injury to either the FO or the lateral plate of the pterygoid process on either side were excluded. One hundred and sixty sides of eighty skulls were eligible. The relationship between the FO and the posterior border of the base of the lateral plate was classified into four types. Among the 160 sides, type III (direct type) was the most common (35%), followed by type I (lateral type, 29%) and type IV (removed type, 21%); type II (medial type) was the least common (15%). Of the 80 specimens, 53 showed the same type bilaterally. In type IV, the posterior border of the base of the lateral plate is disconnected from the FO, so percutaneous procedures for treating trigeminal neuralgia could fail in patients with this type.

Angulation Between the Occipital Condyle and the Hypoglossal Canal: An Anatomical Study With Application in Transcondylar Approaches and Occipital Condyle Screw Placement.

Background A detailed understanding of the relationship between the occipital condyle (OC) and the deeper-lying hypoglossal canal (HC) is necessary for surgeons who place screws into the OC or drill through or around the HC. Therefore, this anatomical study was performed. Methodology A total of 30 skulls (60 sides) underwent an analysis of the angle formed between the long axis of the OC and the HC, i.e., the OC/HC angle. Additionally, the lengths and widths of the OCs and foramen magnum (FM) of each skull were measured using a micrometer. Statistical analyses were performed between the left and right sides, and a Pearson's correlation coefficient was calculated between OC/HC angles and the sizes of the OCs and FM of the skulls. Results The OC/HC angle for the left and right sides ranged from 30 to 56 degrees (mean 46 degrees). The width of the OCs ranged from 9 to 18 mm (mean 13 mm). The length of the OCs was 18 to 31 mm (mean 24 mm). The mean length and width of the FM were 36 mm and 30 mm, respectively. There was no statistically significant difference between the OC/HC angle comparing left and right sides or male or female specimens. Additionally, no statistically significant differences were found between septated and non-septated HC. Pearson's correlation coefficient for left and right OC/HC angles and left and right OC lengths was r = 0.4056 and r = 0.2378, respectively. Pearson's correlation coefficient for left and right OC/HC angles and left and right OC width was r = 0.3035 and r = 0.3530, respectively. Pearson's correlation coefficient for left and right OC/HC angles and the width of the FM was r = 0.2178 and r = 0.2048, respectively. Pearson's correlation coefficient for left and right OC/HC angles and the length of the FM was r = 0.3319 and r = 0.2683, respectively. Conclusions The OC/HC angle as measured here was relatively consistent with no statistically significant differences between sides. We did not find a strong correlation between the width or length of the OC or the width or length of the FM and the OC/HC angles. Therefore, based on our study, surgeons can expect that this angle will range between 30 and 56 degrees (mean 46 degrees). Such knowledge might decrease patient morbidity following invasive procedures involving the OC.

Otosclerosis under microCT: New insights into the disease and its anatomy.

Purpose: Otospongiotic plaques can be seen on conventional computed tomography (CT) as focal lesions around the cochlea. However, the resolution remains insufficient to enable evaluation of intracochlear damage. MicroCT technology provides resolution at the single micron level, offering an exceptional amplified view of the otosclerotic cochlea. In this study, a non-decalcified otosclerotic cochlea was analyzed and reconstructed in three dimensions for the first time, using microCT technology. The pre-clinical relevance of this study is the demonstration of extensive pro-inflammatory buildup inside the cochlea which cannot be seen with conventional cone-beam CT (CBCT) investigation. Materials and Methods: A radiological and a three-dimensional (3D) anatomical study of an otosclerotic cochlea using microCT technology is presented here for the first time. 3D-segmentation of the human cochlea was performed, providing an unprecedented view of the diseased area without the need for decalcification, sectioning, or staining. Results: Using microCT at single micron resolution and geometric reconstructions, it was possible to visualize the disease's effects. These included intensive tissue remodeling and highly vascularized areas with dilated capillaries around the spongiotic foci seen on the pericochlear bone. The cochlea's architecture as a morphological correlate of the otosclerosis was also seen. With a sagittal cut of the 3D mesh, it was possible to visualize intense ossification of the cochlear apex, as well as the internal auditory canal, the modiolus, the spiral ligament, and a large cochleolith over the osseous spiral lamina. In addition, the oval and round windows showed intense fibrotic tissue formation and spongiotic bone with increased vascularization. Given the recently described importance of the osseous spiral lamina in hearing mechanics and that, clinically, one of the signs of otosclerosis is the Carhart notch observed on the audiogram, a tonotopic map using the osseous spiral lamina as region of interest is presented. An additional quantitative study of the porosity and width of the osseous spiral lamina is reported. Conclusion: In this study, structural anatomical alterations of the otosclerotic cochlea were visualized in 3D for the first time. MicroCT suggested that even though the disease may not appear to be advanced in standard clinical CT scans, intense tissue remodeling is already ongoing inside the cochlea. That knowledge will have a great impact on further treatment of patients presenting with sensorineural hearing loss.