Fresh Cadaveric Specimens Research Articles

An Anatomical Study of the Feasibility of the Pectoralis Minor Transfer for Subscapular Deficiency: An Investigation of the Association Between the Transferred Muscle and the Musculocutaneous and Axillary Nerves.

Introduction The purpose of this study was to evaluate the feasibility of transferring the pectoralis minor (PM) in its entirety and assess its relationship with the musculocutaneousnerves (MCN) and axillary nerves (AXN). Methods Sixteen fresh transthoracic cadaver specimens were used. After PM transfer, the following measures were obtained: (a) the distance between the coracoid process (CP) and the subscapularis insertion on the lesser tubercle during external, neutral, and internal rotation. (b) The distances between the CPand PM, PM and musculocutaneous nerve, and PM and the axillary nerve. All measurements were performed using a precision caliper by two independent and blind-to-each-other findings observers. Results The median distance between the CP and PM muscles was 24 ± 7.7 mm, while the width of the coracoid was 24 ± 5.2 mm. PM-MCN distance was 23.25 ± 21.9 mm, CP-MCN distance was 72.1 ± 32.4 mm, and PM-AXN distance was 4.9 ± 0.7 mm. The distance between the coracoid process and lesser tuberosity varied by rotation: 29.2 ± 5.5 mm in internal rotation, 41.1 ± 8.9 mm in neutral rotation, and 51.1 ± 10.7 mm in external rotation. The distance significantly increased between internal and neutral or external rotation (p <0.05), but no significant difference was observed between neutral and external rotation (p > 0.05). Conclusion The distance between the coracoid process and lesser tuberosity increased considerably only between internal and neutral or external rotation positions. Additionally, the importance of identifying the musculocutaneous and axillary nerves and their branches when transferring the pectoralis minor should be highlighted.

A biomechanical investigation comparing a novel bone cement bridging screw system with conventional treatment methods for Kummell’s disease

Based on the characteristics of Kummell’s disease (KD) and related anatomical structures of the thoracolumbar spine, a novel bone cement screw system has been designed to effectively avoid the cement loosening and displacement. This experiment aimed to assess the biological effects of the novel bone cement screw system in KD on fresh cadaveric thoracolumbar spine specimens, thereby discussing its potential application value and providing a foundation for clinical implementation. This study employed a total of 50 fresh female adult cadaver specimens. Each specimen underwent extraction of the T12 to L2 segment followed by the creation of an artificial KD model at the L1 segment and subsequent establishment of five distinct types of bone cement repair models. Model A represents the percutaneous vertebroplasty (PVP) model, Model B combines PVP with unilateral percutaneous pediculoplasty (PPP), Model C combines PVP with bilateral PPP, Model D introduces the novel bone cement screw combined with unilateral PVP, and Model E combines the novel screw with bilateral PVP, each group consists of 10 specimens. Subsequently, the six-axis spine robot was employed to execute cement three-dimensional biomechanical strength tests in six directions, including anterior flexion and posterior extension, left and right lateral bending, as well as left and right rotation. The novel bone cement screw, whether used unilaterally or bilaterally in combination with the PVP model, exhibits significantly reduced bone cement mobility and superior biomechanical stability during anterior flexion, posterior extension, left lateral bending, and right lateral bending (P<0.05).No significant differences were observed among the five models under both left and right rotation (P > 0.05).When comparing the novel bone cement screw combined with PVP unilaterally and bilaterally, no statistically significant difference was observed in the stability of bone cement across all six directions of motion (P>0.05). To conclude, this novel bone cement bridging screw system exhibits superior biomechanical stability compared to commonly used treatments. Furthermore, both unilateral and bilateral implementations of the novel bone cement screw system yield without significant differences observed. These findings present a reliable and innovative approach for clinical management of KD.

Manual Forearm Palpation in Acute Forearm Compartment Syndrome Is Not Accurate

Background: Manual compartment palpation is used as a component of the clinical diagnosis of acute compartment syndrome (ACS), particularly in obtunded patients. However, its utility and accuracy in the upper limb are unknown. The purposes of this study were to assess the accuracy of manual compartment palpation of ACS in the forearm in a cadaveric model and to assess the role of clinician experience in this setting. Methods: Reproducible, sustained elevation of intracompartmental pressure was established in 8 fresh upper-limb cadaveric specimens. The 3 forearm compartments (volar, dorsal, and mobile wad) were randomized to pressures of 20 and 40 mm Hg (negative controls) and 60 and 80 mm Hg (ACS). This was achieved by using fluid infusion and a pressure monitoring system. Orthopaedic clinicians with varying experience (residents, registrars, and consultants) used palpation to assess forearm compartments with known intracompartmental pressures. The examiners were blinded to the compartment pressures and the other examiners’ responses. After the examination, the following 3 questions were answered: (1) Was compartment syndrome present? (2) In which compartment(s) was the pressure elevated? (3) What would be the next management step (fasciotomy or observation)? Results: Manual palpation of compartment pressure had an overall sensitivity of 70%, a specificity of 56%, a positive predictive value of 24%, a negative predictive value of 90%, and a likelihood ratio (LR) of 20.3 (p &lt; 0.001). The sensitivity was similar in detecting ACS in the volar and dorsal compartments (70% and 69%, respectively). The sensitivity and specificity of combined volar and dorsal compartment palpation were 81% and 64% (LR, 16.6; p &lt; 0.001) when performed by residents, 72% and 46% (LR, 4.2; p = 0.040) when performed by registrars, and 58% and 63% (LR, 3.6; p = 0.057) when performed by consultants. All of the compartments that were deemed positive for ACS were recommended for fasciotomy. Conclusions: In our study, manual palpation of compartment pressure had a low accuracy in the diagnosis of ACS of the forearm and was not improved by clinician experience. Clinical Relevance: We recommend against the use of manual palpation of compartment pressure in the diagnosis of forearm ACS in an obtunded patient.

Targeted Muscle Reinnervation in the Upper Arm: A Functional Anatomical Study

BackgroundThe aim of this study was to accurately locate the neural fascicle controlling hand movement in the upper arm, to enhance expression of motor intention after targeted muscle reinnervation. MethodsThe right sides of the median, ulnar and radial nerves were dissected from distal to proximal in 6 fresh cadaver specimens. The sectional location and diameter of the functional fascicle were measured at 10 and 20 cm below the acromion. The diameter of the main muscle branches of muscle reinnervation target muscles was measured. ResultsThe median nerve branch of finger and wrist flexion was mainly located between the 9 and 12 o’clock positions in the plane 10 and 20 cm below the acromion, where the diameter of the nerve fascicle was 2.07 and 2.04 mm, respectively. The ulnar nerve branch of finger and wrist flexion was mainly located between the 8 and 12 o’clock positions, with a diameter of respectively 1.80 and 1.99 mm. The radial branch of finger and wrist extension was mainly located between the 10 and 2 o’clock positions in the plane 10 cm below the acromion and between 6 and 12 o’clock in the plane 20 cm below the acromion, with a diameter of respectively 2.57 and 3.03 mm. ConclusionsThe nerve fascicles innervating the flexor and extensor fingers were distributed in relatively constant regions of the median, ulnar and radial nerve trunks, and their diameters closely matched the muscle branches of the target muscle.

Pitanguy Ligament Preservation in Structural Precision Rhinoplasty.

The Pitanguy ligament is a crucial structure in nasal tip support and in maintaining the integrity of the soft tissue envelope of the nose. In this cadaveric study, we dissected out the Pitanguy ligament on a series of fresh human cadaver specimens to better elucidate the structure of the ligament and its fate in open rhinoplasty. The Pitanguy ligament can act as a tethering force to the nasal tip when reshaping the nasal tip. Release of the Pitanguy ligament alleviated downward tension on the nasal tip, and tip shaping to a more appropriate position demonstrated that this ligament was displaced from its ideal position. In patients seeking rhinoplasty, this structure may require release and reconstruction to successfully alter tip position and avoid supratip deformity.

A novel theory for rapid localization of the transverse-sigmoid sinus junction and “keyhole” in the retrosigmoid keyhole approach: micro-anatomical study, technique nuances, and clinical application

To determine a rapid and accurate method for locating the keypoint and “keyhole” in the suboccipital retrosigmoid keyhole approach. (1) Twelve adult skull specimens were selected to locate the anatomical landmarks on the external surface of the skull.The line between the infraorbital margin and superior margin of the external acoustic meatus was named the baseline. A coordinate system was established using the baseline and its perpendicular line through the top point of diagastric groove.The perpendicular distance (x), and the horizontal distance (y) between the central point of the “keyhole” and the top point of the digastric groove in that coordinate system were measured. The method was applied to fresh cadaveric specimens and 53 clinical cases to evaluate its application value. (1) x and y were 14.20 ± 2.63 mm and 6.54 ± 1.83 mm, respectively (left) and 14.95 ± 2.53 mm and 6.65 ± 1.61 mm, respectively (right). There was no significant difference between the left and right sides of the skull (P > 0.05). (2) The operative area was satisfactorily exposed in the fresh cadaveric specimens, and no venous sinus injury was observed. (3) In clinical practice, drilling did not cause injury to venous sinuses, the mean diameter of the bone windows was 2.0–2.5 cm, the mean craniotomy time was 26.01 ± 3.46 min, and the transverse and sigmoid sinuses of 47 patients were well-exposed. We propose a “one point, two lines, and two distances” for “keyhole” localization theory, that is we use the baseline between the infraorbital margin and superior margin of the external acoustic meatus and the perpendicular line to the baseline through the top point of the digastric groove to establish a coordinate system. And the drilling point was 14.0 mm above and 6.5 mm behind the top point of the digastric groove in the coordinate system.

Feasibility of targeting the cingulate gyrus using high-intensity focused ultrasound on a cadaveric specimen: illustrative case.

Cancer is commonly associated with pain. For patients with advanced cancer and intractable pain, ablative neurosurgical procedures can significantly improve pain and transition patients out of inpatient settings. These procedures are normally invasive, and this poses an important risk in this population. Cingulotomy has been reported to improve pain perception and contribute substantially to the quality of life of cancer patients with refractory pain. One fresh human cadaver specimen was used for the setup. The cingulate gyrus was targeted using intraoperative magnetic resonance images, and osseous aberrations were corrected after coregistration with the preoperative head computed tomography. After accounting for sinuses, membrane folds, and calcifications, a total of 737 elements were available for thermal ultrasound ablation. On high-power sonications, the total energy delivered reached a peak temperature of 57°C (15,050 J, 350 W, 45 seconds) in the right cingulate and 52°C (13,000 J, 405 W, 46 seconds) in the left cingulate. Despite the limitations of using a cadaver model (temperature, vascularization), cingulotomy appears to be feasible using high-intensity focused ultrasound. https://thejns.org/doi/10.3171/CASE2459.

An anatomical road map of the parapharyngeal internal carotid artery in lateral and endoscopic ventral approaches

Objective:To describe the road map of the lateral and endoscopic ventral approaches for the pharyngeal segment of the internal carotid artery, propose a sub-segmentation scheme, systematically and comprehensively understand its anatomical details and relationships with the surrounding structures. Methods:Five fresh cadaveric head specimens（10 sides in total） were dissected through lateral and endoscopic ventral approaches to evaluate the anatomical details of the parapharyngeal internal carotid artery and its relationship with the surrounding structures. Results:From the bifurcation of the common carotid artery to the vertical part of the internal carotid artery, alongside the direction of blood flow, the parapharyngeal internal carotid artery passes through four distinct anatomical tissues. Based on this, the parapharyngeal internal carotid artery can be divided into four sub-segments: nerve, muscle, fascia and osseous sub-segments. The boundaries and important adjacent structures of each segment are described in detail. Conclusion:The anatomical road map of the parapharyngeal internal carotid artery and the sub-segmentation scheme serving as a practical guide to navigate modular endoscopic skull base surgery of the parapharyngeal space while reduce the risk of internal carotid artery injury.

The tibial capsular reflection and septum in posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in posterior cruciate ligament reconstruction.

To investigate the validity of using tibial capsular reflection and septum in the posterior compartment as landmark during posterior cruciate ligament (PCL) reconstruction (PCLR). Anatomic measurements were obtained for 12 fresh human cadaveric knee specimens to observe the spatial position of the tibial insertion of the PCL in relation to the posterior septum and the capsular reflection in the posterior compartment. Sixty patients who underwent reconstruction of the PCL between 2020 and 2023 were also retrospectively investigated. The tibial tunnel was replaced in all patients using the same method (with reference to the tibial capsular reflection and the posterior septum). The placement of the tibial tunnel was assessed using X-ray fluoroscopy intraoperatively and computed tomography and three-dimensional reconstruction postoperatively. All fibres in the tibial insertion of the PCL in the 12 cadaveric specimens were located in the posteromedial compartment, adjacent to the posterior septum. The inferior border of the PCL insertion is adjacent to the tibial capsular reflection, which is attached at the champagne glass drop-off of the posterior tibia. In our previous cases, none of the patients experienced postoperative or intraoperative complications such as neurovascular injury, and the angle between the pin and the PCL facet was 93.1 ± 3.9° as measured on intraoperative radiographs. The mean distance from the centre of the tibial tunnel outlet to the inferior border of the PCL insertion was 5.6 ± 1.1 mm, and the distance from the centre of the tibial tunnel outlet to the outer border of the PCL insertion as a percentage of the length of the inferior border of PCL insertion was 42.2 ± 6.3%. The tibial capsular reflection and septum in the posterior compartment are safe and reliable soft-tissue landmark for tibial tunnel drilling in PCLR. Level Ⅳ.

Contribution of Soft Tissue Passive Forces in Thumb Carpometacarpal Joint Distraction.

Thumb carpometacarpal joint space changes when the surrounding soft tissues including the capsule, ligaments, and tendons are stretched or pulled away. When at rest, joint forces originate from passive contraction of muscles and the involvement of joint capsule and ligaments. Previous biomechanical models of hand and finger joints have mostly focused on the assessment of joint properties when muscles were active. This study aims to present an experimental-numerical biomechanical model of thumb carpometacarpal joint to explore the contribution of tendons, ligaments, and other soft tissues in the passive forces during distraction. Five fresh cadaveric specimens were tested using a distractor device to measure the applied forces upon gradual distraction of the intact joint. The subsequent step involved inserting a minuscule sensor into the joint capsule through a small incision, while preserving the integrity of tendons and ligaments, in order to accurately measure the fundamental intra-articular forces. A numerical model was also used to calculate the passive forces of tendons and ligaments. Before the separation of bones, the forces exerted by tendons and ligaments were relatively small compared to the capsule force, which accounted for approximately 92% of the total applied force. Contribution of tendons and ligaments, however, increased by further distraction. The passive force contribution by tendons at 2-mm distraction was determined less than 11%, whereas it reached up to 74% for the ligaments. The present study demonstrated that the ligament-capsule complex plays significant contribution in passive forces of thumb carpometacarpal joint during distraction.

Microsurgical anatomy of the olfactory filaments in the nasal mucosa.

The aim of this study was to examine the distribution of olfactory filaments (OFs) in the nasal mucosa to facilitate preservation of olfactory function in endonasal approaches and preparation of a nasoseptal flap. One formalin-fixed and 9 fresh cadaveric silicone-injected specimens with 20 total sides were studied to measure the distance of the OFs to the anatomical landmarks and compare the OF presence in the nasal septum mucosa (NSM) and ethmoidal mucosa (EM). The mean distance from the first to the last OF was 19.37 ± 2.16 mm in the NSM and 23.44 ± 5.42 mm in the EM. The NSM had a mean of 7.55 ± 1.31 OFs and the EM had 14.3 ± 1.78. Average OF lengths were measured at 6.44 ± 1.48 (range 3.75-12.40) mm in the NSM and 8.05 ± 1.76 (range 4.14-13.20) mm in the EM. The mean values of the EM measurements were compared with those of the NSM; the number of OFs, the distance between the first and last OF, the average OF length, and the number of OFs between anterior and posterior ethmoidal arteries in the NSM were significantly less (p < 0.05) than those in the EM. The distance between the first OF to the nasal bone on the NSM was greater than on the EM. Compared with the EM, the OFs are significantly fewer in number and smaller in size in the NSM. The uppermost edge of the nasoseptal flap incision in the NSM might be safer to start below 12 mm from the cribriform plate for OF protection.

Age changes in Corpus Callosum among Indian cadaver specimens: a normative study.

During neurosurgeries like corpus callosotomy (palliative procedure performed in case of intractable seizures) surgical separation of corpus callosum is required. In order to perform the surgical separation of corpus callosum, one needs to have complete knowledge about anatomy and morphometry of corpus callosum. The current study was carried out in order to establish the normative data about morphometry of corpus callosum across various age groups. Thirty fresh human cadaveric brain specimens were used. The two cerebral hemispheres were separated from midline. The measurement of length of corpus callosum and thickness of its various parts was carried out on both the cerebral hemispheres. In the age group of 25-45 years the mean length, thick-ness of genu, body, splenium and rostrum was found to be 76.91 ± 3.78 mm, 7.61 ± 0.79 mm, 4.93 ± 0.49 mm, 9.86 ± 1.43 mm, 3.07 ± 0.37 mm respectively. In the age group of 45.1-65 years the length, thickness of genu, body, splenium and rostrum recorded were 72.49 ± 3.88 mm, 11.57 ± 2.23 mm, 7.07 ± 2.81 mm, 10.20 ± 1.68 mm, 4.22 ± 1.15 mm respectively. In the age group of 65.1-85 years the mean reading of length, thickness of genu, body, splenium and rostrum were 70.20 ± 5.69 mm, 10.45 ± 1.64 mm, 5.51 ± 0.86 mm, 9.61 ± 1.09 mm, 3.97 ± 0.79 mm respectively. In the age group of >85 years the length, thickness of genu, body, splenium and rostrum recorded were 69.28 ± 4.66 mm, 9.31 ± 1.44 mm, 5.18 ± 0.84 mm, 8.56 ± 2.47 mm, 2.69 ± 0.76mm respectively. This data would be useful for neurosurgeons in order to perform transcallosal surgeries in safer way as well as for psychiatrics and radiologists while analysis the scans of patients with psychiatric patients.

Anatomical Structures at Risk in Percutaneous Preparation Talonavicular Fusion.

The stability of the hindfoot greatly relies on the integrity of the talonavicular joint. Pathologies affecting this joint often necessitate fusion. Our study explores the risks posed to neurovascular and tendon structures during simulated percutaneous talonavicular joint preparation for fusion. In 9 fresh cadaver specimens, the talonavicular joint was accessed through two portals. A 2-mm Shannon burr was employed for joint surface preparation with distraction provided by a pin-based distractor. Dissections were performed to assess potential damage to critical structures, including the dorsalis pedis artery, superficial and deep peroneal nerves, extensor hallucis longus (EHL), and tibialis anterior (TA) tendons. The dorsal portal site was found to be significantly closer to important structures compared to the medial portal site. The Shannon burr made contact with various structures, with a single transection identified for both deep and superficial peroneal nerve branches. During the dorsal portal site approach, potential injury to the EHL tendon was identified as concern. This study sheds light on the potential risks associated with percutaneous dorsal and medial joint preparation approaches using a Shannon burr.Level of Evidence:Level V, mechanism-based reasoning..

Morphometric Comparison of Endoscopic Endonasal Transpterygoid and Precaruncular Contralateral Medial Transorbital Approaches to Sphenoid Sinus Lateral Recess.

The endoscopic endonasal transpterygoid approach (TPA), minimally invasive compared with the sublabial transmaxillary and transcranial approaches, still accounts for morbidity in benign lateral recess of sphenoid sinus (LRSS) pathologies. Others have suggested an alternative route to the LRSS, the endoscopic contralateral medial transorbital approach (cMTO). However, no quantitative evidence exists to support the clinical application of this approach. This cadaveric study, in a controlled laboratory setting, provides a morphometric comparison of the TPA and cMTO for accessing the LRSS. The study also details the anatomy and technical nuances for optimizing the cMTO corridor. Ten fresh preinjected human cadaveric specimens (20 sides) were dissected with neuronavigation, completing endoscopic cMTO and TPA on each side. Four parameters-working distance to lateral recess, surgical exposure area, angle of attack (AoA), and surgical freedom-were measured for each approach. Relevant osteological measurements in 10 dried human skulls were recorded. The mean distance from the superior margin of the lacrimal sac impression to the inferior margin of the trochlear fossa was 10.29 ± 1.13 mm, and that from the anterior ethmoidal artery foramina to the posterior lacrimal crest was 9.63 ± 1.23 mm. The mean exposure area around the LRSS was significantly higher in TPA (614.09 ± 40.38 mm2) than in cMTO (391.19 ± 59.01 mm2, P = .001). The mean AoA was 9.83° and 10.24° in the cMTO and TPA, respectively, in the craniocaudal direction (P = .529). In the horizontal plane, it was 9.29° and 10.76° (P = .012). There was no significant difference in surgical freedom between the cMTO and TPA (804.61 and 806.05 mm3, respectively; P = .993). Although comparatively limited exposure area, the cMTO approach has a similar AoA and surgical freedom as TPA and offers better visualization and ergonomic advantages. cMTO provides a feasible, less morbid, multiport technique for benign sphenoid sinus lateral recess pathologies.

Distal insertion of the clavicular portion of pectoralis major muscle: anatomical study.

Several descriptions of the anatomy of the pectoralis major (PM) have been published. However, the precise description of its distal humeral insertion, which is involved in traumatic tears, remains controversial. The distal tendon is classically described as being made of two layers, one anterior (ALPM) and one posterior (PLPM), which regroup at their distal edge. The clavicular head (CH) participates in the ALPM according to most authors. However, others describe a more superficial termination in a close relationship with the deltoid humeral insertion. The objective of this anatomical work is to precisely describe the anatomy of the CH and its relationship with the rest of the distal PM tendon and the distal deltoid tendon. Twenty-three fresh cadaveric specimens were dissected (41 shoulders). The entire PM as well as the deltoid were exposed. Several measurements were collected to establish the relationships between the distal tendon of the CH and the PM, the deltoid and the bony landmarks. In all cases, the CH muscular portion sits on the ALPM but does not participate in the connective structure of the PM distal tendon. The inferolateral part of its distal end gives a thin tendinous portion that inserts lower on the humerus in conjunction with the distal tendon of the deltoid. In 24.4%, this tendon was more difficult to isolate but was always observed. The distal tendon of the PM only comes from the muscle fibres of its sternal head. The CH fibres do not contribute to this tendon but appear to terminate in a separate tendon fusing with the humeral insertion of the deltoid: the deltopectoral tendon. This could explain the different patterns of tears observed in clinical practice.

Anatomic study and clinical application of iliac crest chimeric tissue flap

To conduct anatomical study on the iliac crest chimeric tissue flap and summarize its effectiveness of clinical application in repairing limb wounds. Latex perfusion and anatomical study were performed on 6 fresh adult cadaver specimens with 12 sides, to observe the initial location, distribution, quantity, and direction of the common circumflexa iliac artery, the deep circumflexa iliac artery, and the superficial circumflexa iliac artery, and to measure their initial external diameter. Between December 2020 and September 2022, the iliac crest chimeric tissue flap repair was performed on 5 patients with soft tissue of limbs and bone defects. There were 3 males and 2 females, with an average age of 46 years (range, 23-60 years). Among them, there were 3 cases of radii and skin soft tissue defects and 2 cases of tibia and skin soft tissue defects. The length of bone defects was 4-8 cm and the area of skin soft tissue defects ranged from 9 cm×5 cm to 15 cm×6 cm. The length of the iliac flap was 4-8 cm and the area of skin flap ranged from 12.0 cm×5.5 cm to 16.0 cm×8.0 cm. The donor sites were directly sutured. Anatomical studies showed that there were 10 common circumflex iliac arteries in 5 specimens, which originated from the lateral or posterolateral side of the transition between the external iliac artery and the femoral artery, with a length of 1.2-1.6 cm and an initial external diameter of 0.8-1.4 mm. In 1 specimen without common circumflexa iliac artery, the superficial and deep circumflex iliac arteries originated from the external iliac artery and the femoral artery, respectively, while the rest originated from the common circumflex iliac artery. The length of superficial circumflex iliac artery was 4.6-6.7 cm, and the initial external diameter was 0.4-0.8 mm. There were 3-6 perforator vessels along the way. The length of deep circumflex iliac artery was 7.8-9.2 cm, and the initial external diameter was 0.5-0.7 mm. There were 3-5 muscular branches, 4-6 periosteal branches, and 2-3 musculocutaneous branches along the way. Based on the anatomical observation results, all iliac crest chimeric tissue flaps were successfully resected and survived after operation. The wounds at recipient and donor sites healed by first intention. All patients were followed up 8-24 months, with an average of 12 months. The tissue flap has good appearance and soft texture. X-ray film reexamination showed that all the osteotomy healed, and no obvious bone resorption was observed during follow-up. The common circumflex iliac artery, deep circumflex iliac artery, and superficial circumflex iliac artery were anatomically constant, and it was safe and reliable to use iliac crest chimeric tissue flap in repairing the soft tissue and bone defects of limbs.

Anterior Transarticular Crossing Screw Fixation for Atlantoaxial Joint Instability: A Biomechanical Study.

To evaluate the biomechanical stability of anterior transarticular crossing screw (ATCS) and compare it with anterior transarticular screw (ATS) which may provide basic evidence for clinical application. Eight human fresh cadaveric specimens (occiput-C4) were tested with 5 conditions including the intact status, the injury status (type II odontoid fracture), the injury+ATS fixation status (traditional bilateral ATS fixation); the injury+unilateral ATCS fixation status; and the injury+bilateral ATCS fixation status. Specimens were applied to a pure moment of 1.5 Nm in flexion-extension, lateral bending, and axial rotation, respectively. The range of motions (ROMs) and the neutral zones (NZs) of C1 to C2 segment were calculated and compared between 5 status. ATS and ATCS fixations significantly reduced the motions in all directions when compared with the intact and injury statues (p < 0.05). In flexion-extension, the ROMs of ATS, unilateral ATCS, and bilateral ATCS were 4.7° ± 2.5°, 4.1° ± 1.9°, and 3.2° ± 1.2°, respectively. Bilateral ATCS resulted in a significant decrease in ROM in flexion-extension when compared with ATS and unilateral ATCS (p = 0.035 and p = 0.023). In lateral bending and axial rotation, there was no significant difference in ROM between the 3 fixations (p > 0.05). Three fixations resulted in similar NZs in all directions (p > 0.05). ATCS is a biomechanically effective alternative or supplemental method for atlantoaxial instability.

Biomechanical Study of Horizontal Screw-screw Crosslink in C1-2 Pedicle Screw-rod Fixation.

This is a biomechanical study in vitro. To investigate the biomechanical differences between horizontal rod-rod crosslink (hR-R CL) and the horizontal screw-screw crosslink (hS-S CL) implementation in C1-2 pedicle screw-rod (C1-2 PSR) fixation. To improve internal fixation stability, transverse connector (TC) is used in C1-2 PSR to increase torsional stiffness. The connection mode of horizontal connection includes hR-R CL and hS-S CL. hS-S CL adopted in C1-2 PSR was rarely reported and its biomechanics are still unclear. Six fresh cadaveric cervical spine specimens were each tested as an Intact model, then modified and tested as an Instability model (unstable odontoid fractures), and then as 3 internal fixation models, including C1-2 PSR, C1-2 pedicle screw-rod+horizontal rod-rod crosslink (C1-2 PSR+ hR-R CL), C1-2 pedicle screw-rod+horizontal screw-screw crosslink (C1-2 PSR+ hS-S CL). The ROM of the C1-2 segments was measured by applying 1.5nm load in 6 loading conditions, including flexion-extension (FE), left and right lateral bending (LB), and left and right axial rotation (AR). The C1-2 PSR+hR-R CL and C1-2 PSR+hS-S CL models, respectively, showed 60% and 75% lower ROM than the C1-2 PSR model in LB and AR conditions ( P <0.05). ROM was comparable between the C1-2 PSR+hR-R CL and the C1-2 PSR+hS-S CL models in all loading conditions ( P >0.05). Both types of crosslinks showed superior C1-2 stability under LB and AR conditions than PSR without crosslinks. The C1-2 segment stability was comparable between the 2 types of crosslinks themselves.

Olfactory drug delivery with intranasal sprays after nasal midvault reconstruction

Conductive olfaction and nose to brain drug delivery are important processes that remain limited by inadequate odorant or drug delivery to the olfactory airspace. Primary challenges include anatomic barriers and poor targeting to the olfactory region. This study uses computational fluid dynamics to investigate the effects of nasal midvault surgery on olfactory drug delivery with intranasal sprays. Soft tissue elevation, spreader flaps, and spreader grafts were performed on two fresh cadaveric specimens, using computed tomography for airway reconstruction. Nasal airflow and drug particle transport simulations were performed under these conditions: inhalation rate (15, 30 L/min), spray velocity (1, 5, 10 m/s), spray location (top, bottom, center, medial, lateral), head position (upright, supine, forward, backward), and particle size (1–100 µm). Simulation results were used to calculate drug particle deposition to the olfactory airspaces and bulbs. Total olfactory deposition was < 5% but attained a maximum of 36.33% when sorted by particle size. There was no association between nasal midvault surgery and olfactory deposition. No single parameter or technique demonstrated superior olfactory deposition, but smaller particle size, slower spray velocity, and higher inhalation rate tended to optimize olfactory deposition, providing important implications for future intranasal spray and drug design to target the olfactory airspace.

Comparison of medial tibiofemoral joint mechanics between all-suture anchors and transtibial pullout technique for posterior medial meniscal root tears

BackgroundThe posterior medial meniscal root tear (PMMRT) seriously impacts the tibiofemoral joint biomechanics. Two available techniques for PMMRT repair include the transtibial pullout (TPO) repair and all-suture anchor (ASA) repair techniques. These techniques have not been compared biomechanically.MethodsA total of 20 fresh porcine cadaveric knee specimens were used. All 20 knees were randomly and evenly distributed into four groups (five specimens per group): (1) intact posterior meniscal root, (2) PMMRT, (3) TPO repair technique for PMMRT, and (4) ASA repair technique for PMMRT. The tibiofemoral contact mechanics were investigated using a pressure sensor. All knee specimens were tested by being loaded with 600 N axial compressive force at three different flexion angles (0°, 45°, and 90°). The contact surface area, contact pressure, peak pressure, and time-zero displacement were recorded.ResultsThe PMMRT caused a significant decrease in contact surface area, an increase in contact pressure, and peak pressure from the reference values observed in the intact meniscus group (P = 0.05, 0.016, and 0.008, respectively). After fixation, no significant difference was observed between the ASA and intact group. Meanwhile, significant differences were found between the TPO and intact group in terms of contact surface area, contact pressure, and peak pressure. In the comparison between the two techniques, the ASA group demonstrated higher contact surface area than the TPO group at the average knee flexion angle (p = 0.05).ConclusionFor most testing conditions, the ASA technique demonstrated superior biomechanical property in terms of contact surface area compared with the TPO technique under compressive loading conditions. The ASA technique could also restore the tibiofemoral contact mechanics to be comparable with those of the native intact knee. Meanwhile, a significant difference in tibiofemoral mechanics, compared with the intact knee, could be observed in the TPO technique.