Fresh-frozen Specimens Research Articles

Effects and risks of performing a single incision endoscopic plantar fasciotomy — An anatomical study

BackgroundChronic plantar fasciitis with insufficient improvement after conservative treatment can be addressed by surgery. Endoscopic plantar fasciotomy using a single incision technique is an innovative treatment strategy. The aim of this study was to evaluate the effects and potential risks of damaging anatomical structures when performing this technique. Methods40 fresh-frozen foot specimens underwent single incision endoscopic plantar fasciotomy. Operations of group A (n = 20) were done by an experienced surgeon, operations of group B (n = 20) were done by unexperienced residents. ResultsIn both groups, all major vessels or nerves remained undamaged. Sufficient transection (>90%) was found in 16 of 20 specimens (group A) and 10 of 20 specimens (group B) (p = 0.047). ConclusionsOur results show that single incision endoscopic plantar fasciotomy can be safely performed even by unexperienced surgeons. In contrast to that, complete transection of the medial fascicle is dependent on the surgeon’s experience.

Comparative Analysis of 3 Techniques of Scapholunate Reconstruction for Dorsal Intercalated Segment Instability

The combination of scaphoid rotatory subluxation, dorsal intercalated segment instability, and dorsal scaphoid translation (DST) constitutes stage 5 scapholunate dissociation in the modified classification system of Garcia-Elias. The purpose of this study was to compare the static radiographic outcomes of reduction and association of the scaphoid and lunate (RASL), three-ligament tenodesis (TLT), and anatomic front and back (ANAFAB) reconstructions for stage 5 scaphoid and lunate malrotation and translation. Stage 5 scapholunate dissociation was created in 15 fresh-frozen specimens by cutting the scapholunate interosseous ligament, long radiolunate ligament, dorsal intercarpal ligament, and scaphotrapeziotrapezoid ligament complex. Specimens were randomized to receive 1 of the 3 reconstructive techniques. Radiolunate angle (RLA), scapholunate angle, scapholunate gap, and DST were measured in static fluoroscopic posteroanterior and lateral views in 3 conditions: baseline, injured, and reconstructed. Reduction and association of the scaphoid and lunate showed an improved correction of scapholunate gap compared with TLT and ANAFAB. Anatomic front and back demonstrated an improved correction in RLA and scapholunate angle compared with RASL but not TLT. When the reconstruction was compared with baseline, there was a persistent lunate extension for TLT (RLA and scapholunate angle) and RASL (RLA); however, no significant difference in any parameter was found with ANAFAB. Anatomic front and back significantly improved DST, whereas TLT and RASL did not. In this cadaveric model of scapholunate dissociation with dorsal intercalated segment instability and DST, each of the 3 repairs had different effects on carpal posture and alignment. While only RASL statistically improved scapholunate gap, only ANAFAB significantly improved DST. Both TLT and RASL improved radiographic parameters; however, each had a persistent increase in the lunate extension following reconstruction. It may be prudent to consider different reconstructive techniques for different stages of scapholunate instability. Anatomic front and back, a repair that addresses both dorsal and volar ligament stabilizers, provides improved reduction of dorsal intercalated segment instability and DST in stage 5 scapholunate dissociation.

Abstract 653: Clinical value and oncogenic role of METTL3 expression in gastric cancer patients

Abstract Background: Gastric cancer (GC) is one of the most common cancers and leading cause of cancer-related deaths worldwide, primarily because of rapid disease progression to advanced stages and highly malignant potential. Methyltransferase-like 3 (METTL3) is a crucial component of the m6A methyltransferase complex, and plays pivotal roles in tumour progression. This study investigated the prognostic significance of METTL3 expression in gastric cancer (GC). Methods: We assessed expression levels of METTL3 by immunohistochemistry in formalin-fixed paraffin-embedded (FFPE) tissue specimens from one hundred fifty-eight GC patients. Propensity score matching (PSM) analysis was performed to clarify its prognostic potential. The METTL3 gene expression was also investigated in fresh frozen specimens from another independent cohort of fifty-seven GC patients to establish its clinical relevance. Knockdown of METTL3 by siRNA transfection was performed to evaluate its function in vitro. Results: METTL3 expression was significantly higher in cancerous tissues vs. corresponding normal mucosa (P<0.0001), and high METTL3 staining group was significantly associated with males (P=0.029), an advanced T stage (P=0.0002), the presence of venous invasion (P<0.0001), lymphatic vessel invasion (P=0.011), lymph node metastasis (P=0.004), distant metastasis (P=0.0004), and advanced TNM stage classification (P=0.0001) in the FFPE cohort of GC patients. Survival curve analysis showed that patients with increased expression of METTL3 showed poorer prognosis in terms of both overall survival (OS: P<0.0001, log-rank test) and disease-free survival (DFS: P=0.0005, log-rank test) compared to those with low expression. Multivariate analysis revealed that increased expression of METTL3 was an independent prognostic factor for overall survival (OS: hazard ratio (HR), 3.24; 95% confidence interval (CI), 1.57-6.68; p=0.001) and disease-free survival (DFS: HR, 2.4; 95% CI, 1.12-5.16; p=0.025) in the FFPE cohort of GC patients. PSM analysis revealed that elevated METTL3 expression was significantly associated with poor survival outcomes (OS: P=0.05; DFS: P=0.038; log-rank test), which was subsequently validated in another cohort of fresh frozen specimens (OS: p=0.007; DFS: p=0.029; log-rank test). The knockdown of METTL3 inhibited proliferation, invasion, migration, and anoikis resistance in GC cells. Conclusion: METTL3 expression may be used as a clinically feasible prognostic marker and could serve as a potential therapeutic target in GC patients. Citation Format: Yoshinaga Okugawa, Yuji Toiyama, Chengzeng Yin, Ma Ruiya, Akul Goel, Takashi Ichikawa, Hiroki Imaoka, Takahito Kitajima, Tadanobu Shimura, Mikio Kawamura, Hiromi Yasuda, Hiroyuki Fujikawa, Takeshi Yokoe, Ikuyo Mochiki, Masaki Ohi, Kaname Nakatani. Clinical value and oncogenic role of METTL3 expression in gastric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 653.

Biomechanical comparison of screw, tightrope and novel double endobutton in the treatment of tibiofibular syndesmotic injuries

BackgroundAdequate reduction and stabilization of the syndesmosis are significant to prevent early degeneration of the ankle joint and get better clinical outcomes. However, the routine surgical methods have diffierent limitations. The purpose of this study was to develop a novel double Endobutton fixation to treat the distal tibiofibular syndesmotic injuries, and determine whether the novel double Endobutton fixation demonstrates a better biomechanical property compare with the intact syndesmosis, the screw fixation and the Tightrope fixation. MethodsTwenty-four normal fresh-frozen ankle specimens with a mean age of 42 ± 8 (range, 28–62) years were randomly divided equally into four groups: (1) the intact group, (2) the screw group, (3) the Tightrope group, (4) the Endobutton group. 3D printer technology was used to establish the personalized distal tibiofibular syndesmotic navigation modules to determine the accurate bone tunnel. Axial loading was applied in five ankle positions: neutral position, dorsiflexion, plantar flexion, varus and valgus. Rotation torque was applied in two ankle rotation of the neutral position: internal and external. ResultsIn most situations, the displacements of the intact group were larger than the screw group, the Tightrope group and the Endobutton group (P < .05), and the displacements of the screw group were smaller than other three groups (P < .05). The displacements of the double Endobutton group were slightly larger than the Tightrope group but no significant differences were found between these two groups except in the dorsiflexion position of axial loading experiments (P < .05). The novel double Endobutton fixation was steadier than intact syndesmosis and more micromotional than screw fixation. ConclusionOur study demonstrated that the novel double Endobutton can be considered as the better fixation in treatment of distal tibiofibular syndesmotic injuries. Level of EvidenceLevel III, retrospective comparative study

Novel Radiographic Indexes for Elbow Stability Assessment: Part A\u2014Cadaveric Validation

IntroductionElbow bony stability relies primarily on the high anatomic congruency between the humeral trochlea and the ulnar greater sigmoid notch. No practical tools are available to distinguish different morphotypes of the proximal ulna and herewith predict elbow stability. The aim of this study was to assess inter-observer reproducibility, evaluate diagnostic performance and determine responsiveness to change after simulated coronoid process fracture for three novel elbow radiographic indexes.MethodsTen fresh-frozen cadaver specimens of upper limbs from human donors were available for this study. Three primary indexes were defined, as well as two derived angles: Trochlear Depth Index (TDI); Posterior Coverage Index (PCI); Anterior Coverage Index (ACI); radiographic coverage angle (RCA); olecranon–diaphisary angle (ODA). Each index was first measured on standardized lateral radiographs and subsequently by direct measurement after open dissection. Finally, a type II coronoid fracture (Regan and Morrey classification) was created on each specimen and both radiographic and open measurements were repeated. All measurements were conducted by two orthopaedic surgeons and two dedicated musculoskeletal radiologists.ResultsAll three indexes showed good or moderate inter-observer reliability and moderate accuracy and precision when compared to the gold standard (open measurement). A significant change between the radiographic TDI and ACI before and after simulated coronoid fracture was observed [TDI: decrease from 0.45 ± 0.03 to 0.39 ± 0.08 (p = 0.035); ACI: decrease from 1.90 ± 0.17 to 1.58 ± 0.21 (p = 0.001)]. As expected, no significant changes were documented for the PCI. Based on these data, a predictive model was generated, able to identify coronoid fractures with a sensitivity of 80% and a specificity of 100%.ConclusionNew, simple and easily reproducible radiological indexes to describe the congruency of the greater sigmoid notch have been proposed. TDI and ACI change significantly after a simulated coronoid fracture, indicating a good responsiveness of these parameters to a pathological condition. Furthermore, combining TDI and ACI in a regression model equation allowed to identify simulated fractures with high sensitivity and specificity. The newly proposed indexes are, therefore, promising tools to improve diagnostic accuracy of coronoid fractures and show potential to enhance perioperative diagnostic also in cases of elbow instability and stiffness.Level of evidenceBasic science study.Clinical relevanceThe newly proposed indexes are promising tools to improve diagnostic accuracy of coronoid fractures as well as to enhance perioperative diagnostic for elbow instability and stiffness.

Accessibility of the metatarsal head comparing distraction and plantarflexion in a 2‐portal technique for first metatarsophalangeal (MTP 1) joint arthroscopy

Introduction/Purpose Arthroscopic treatment of osteochondral lesion of the first metatarsophalangeal (MTP1) joint is an established procedure. Non-invasive distraction is most commonly applied when a dorsal 2-portal technique is used. Alternatively, plantarflexion can be utilized. In order to compare the arthroscopic reachability of the first metatarsal head, a laboratory study in anatomical specimens was performed. Methods Twenty matched pairs (n=40) of fresh-frozen lower leg specimens were obtained and randomly assigned into two groups, a distraction (DIS) and a plantarflexion (PF) group, respectively. A standard 2-portal approach (dorsolateral and dorsomedial portals) with a 1.9mm 30° scope was used. The arthroscopic accessibility of the first metatarsal head was evaluated using chondral picks. Markings at the metatarsal heads were made intraoperatively and measured after exarticulation. Results In the DIS group the mean accessible area was 58.03%, while the accessible area in the PF group was 55.93%. Though there is a small difference between the two groups, this difference was not statistically significant (p=0.51). Range of motion of the MTP 1 joint did not affect reachability. In one specimen (2.5%) the dorsomedial hallucal nerve was injured during arthroscopy. Conclusion Access to the MTP1-joint for the treatment of osteochondral lesions is similar using distraction or plantarflexion during arthroscopy. The plantarflexion technique has the advantage of less surgical equipment needed. The dorsomedial hallucal nerve is at danger at the medial portal.

Forearm Interosseous Ligaments: Anatomical and Histological Analysis of the Proximal, Central, and Distal Bands

To characterize and compare the histological structure of the proximal, central, and distal bands of the interosseous membrane (IOM) of the human forearm in fresh-frozen specimens. The IOMs from 16 fresh-frozen left forearm specimens were carefully dissected and examined. The footprint areas of the proximal, central, and distal IOM bands were measured in 6 specimens. The histological characteristics of the IOM bands were evaluated using hematoxylin-eosin and Masson trichrome staining protocols in 10 specimens as histological analysis necessitated an intact footprint. The footprint areas of the IOM were measured using an image processing program. The insertion complex was assessed using a light microscope. Histological assessment revealed that the IOM structure demonstrated similarities with ligament structure. The average footprint areas of the proximal, central, and distal bands at the radial site were 11.1 ± 0.8, 180.4 ± 30.4, and 10.7 ± 1.3 mm2, respectively. At the ulnar site, they were 11.0 ± 1.1, 171.8 ± 30.1, and 10.7 ± 1.2 mm2, respectively. The insertion complex of the IOM into the bone comprised 4 layers: (1) interwoven collagen, (2) oblique collagen, (3) mineralized fibrocartilage (tidemark), and (4) lamellar bone. The average tidemark zone thicknesses of the proximal, central, and distal bands were 20.1 ± 6.3, 107.8 ± 22.9, and 20.6 ± 4.7 μm, respectively at the radial site and 12.0 ± 4.5, 85.7 ± 23.2, and 13.5 ± 6.9 μm, respectively at the ulnar site. In this study, we confirm that the histological characteristics of the IOM are similar to those of ligaments. Compared with the proximal and distal bands, the central band has a greater footprint area and thicker tidemark zone. If surgical reconstruction is performed, the size and histological characteristics of the graft should be similar to those of the native ligaments.

Human breast microbiome correlates with prognostic features and immunological signatures in breast cancer

BackgroundCurrently, over half of breast cancer cases are unrelated to known risk factors, highlighting the importance of discovering other cancer-promoting factors. Since crosstalk between gut microbes and host immunity contributes to many diseases, we hypothesized that similar interactions could occur between the recently described breast microbiome and local immune responses to influence breast cancer pathogenesis.MethodsUsing 16S rRNA gene sequencing, we characterized the microbiome of human breast tissue in a total of 221 patients with breast cancer, 18 individuals predisposed to breast cancer, and 69 controls. We performed bioinformatic analyses using a DADA2-based pipeline and applied linear models with White’s t or Kruskal–Wallis H-tests with Benjamini–Hochberg multiple testing correction to identify taxonomic groups associated with prognostic clinicopathologic features. We then used network analysis based on Spearman coefficients to correlate specific bacterial taxa with immunological data from NanoString gene expression and 65-plex cytokine assays.ResultsMultiple bacterial genera exhibited significant differences in relative abundance when stratifying by breast tissue type (tumor, tumor adjacent normal, high-risk, healthy control), cancer stage, grade, histologic subtype, receptor status, lymphovascular invasion, or node-positive status, even after adjusting for confounding variables. Microbiome–immune networks within the breast tended to be bacteria-centric, with sparse structure in tumors and more interconnected structure in benign tissues. Notably, Anaerococcus, Caulobacter, and Streptococcus, which were major bacterial hubs in benign tissue networks, were absent from cancer-associated tissue networks. In addition, Propionibacterium and Staphylococcus, which were depleted in tumors, showed negative associations with oncogenic immune features; Streptococcus and Propionibacterium also correlated positively with T-cell activation-related genes.ConclusionsThis study, the largest to date comparing healthy versus cancer-associated breast microbiomes using fresh-frozen surgical specimens and immune correlates, provides insight into microbial profiles that correspond with prognostic clinicopathologic features in breast cancer. It additionally presents evidence for local microbial–immune interplay in breast cancer that merits further investigation and has preventative, diagnostic, and therapeutic potential.

Limited effect of anatomical insert geometry on in vitro laxity in balanced anatomic posterior cruciate ligament retaining total knee arthroplasty.

The present study assessed the effect of insert articular surface geometry (anatomical versus conventional insert design) on anteroposterior (AP) translation and varus-valgus (VV) laxity in balanced posterior cruciate ligament (PCL) retaining total knee arthroplasty (TKA). Secondly, we evaluated if the AP translation and VV laxity in the reconstructed knee resembled the stability of the native knee. Nine fresh-frozen full-leg cadaver specimens were used in this study. After testing the native knee, anatomical components of a PCL-retaining implant were implanted. The knee joints were subjected to anteriorly and posteriorly directed forces (at 20° and 90° flexion) and varus-valgus stresses (at 20°, 45° and 90° flexion) in both non-weightbearing and weightbearing situations in a knee kinematics simulator. Measurements were performed in the native knee, TKA with anatomical insert geometry (3° built-in varus, medial concave, lateral convex), and TKA with symmetrical insert geometry. In weightbearing conditions, anterior translations ranged between 2.6 and 3.9mm at 20° flexion and were < 1mm at 90° flexion. Posterior translation at 20° flexion was 2.7mm for the native knee versus 4.0mm (p = 0.047) and 7.0mm (p = 0.02) for the symmetrical insert and the anatomical insert, respectively. Posterior translation at 90° flexion was < 1.1mm and not significantly different between the native knee and insert types. In non-weightbearing conditions, the anterior translation at 20° flexion was 5.9mm for the symmetrical and 4.6mm for the anatomical insert (n.s.), compared with 3.0mm for the native knee (p = 0.02). The anterior translation at 90° flexion was significantly higher for the reconstructed knees (anatomical insert 7.0mm; symmetrical insert 9.2mm), compared with 1.6mm for the native knee (both p = 0.02). Varus-valgus laxity at different flexion angles was independent of insert geometry. A valgus force in weightbearing conditions led to significantly more medial laxity (1°-3° opening) in the native knee at 45° and 90° flexion compared with the reconstructed knee for all flexion angles. Insert geometry seems to have a limited effect with respect to AP translation and VV laxity, in the well-balanced PCL-retaining TKA with an anatomical femoral component. Secondly, AP translation and VV laxity in the reconstructed knee approximated the laxity of the native knee.

Gracilis and semitendinosus moment arm decreased by fascial tissue release after hamstring harvesting surgery: a key parameter to understand the peak torque obtained to a shallow angle of the knee.

Semitendinosus and gracilis muscles whose tendons are used in surgical reconstruction of the anterior cruciate ligament maintain their contractile ability, but the peak torque angle of hamstring muscles shifted to a shallow angle postoperatively. The goal was to quantify the influence of the myofascial structures on instantaneous moment arms of knee muscles to attempt explaining the above-mentioned post-surgical observations. Hamstring harvesting procedures were performed by a senior orthopaedic surgeon on seven lower limbs from fresh-frozen specimens. Femoro-tibial kinematics and tendons excursion were simultaneously recorded at each step of the surgery. No significant difference was demonstrated for instantaneous moment arm of gracilis during anterior cruciate ligament surgery (84% of the maximum intact values; P ≥ 0.05). The first significant semitendinosus moment arm decrease was observed after tendon harvesting (61% of the maximum intact values; p ≤ 0.005). After hamstring harvesting, the maximum and minimum moment arm (both gracilis and semi tendinosus) shifted to a shallow angle and 90°, respectively. Moment arm modifications by paratenons and the loose connective tissue release are essential to understand the peak torque obtained to a shallow angle. Basic science study, biomechanics.

Secondary Patellar Resurfacing in TKA: A Combined Analysis of Registry Data and Biomechanical Testing.

The German Arthroplasty registry (EPRD) has shown that different prosthesis systems have different rates of secondary patellar resurfacing: four years after implantation, the posterior-stabilized (PS) Vega prosthesis has a 3.2% risk of secondary patellar resurfacing compared to the cruciate-retaining (CR) Columbus prosthesis at 1.0% (both Aesculap AG, Tuttlingen, Germany). We hypothesized that PS implants have increased retropatellar pressure and a decreased retropatellar contact area compared to a CR design, which may lead to an increased likelihood of secondary patellar resurfacing. Eight fresh frozen specimens (cohort 1) were tested with an established knee rig. In addition, a possible influence of the registry-based patient collective (cohort 2) was investigated. No significant differences were found in patient data–cohort 2-(sex, age). A generally lower number of PS system cases is noteworthy. No significant increased patella pressure could be detected with the PS design, but a lower contact area was observed (cohort 1). Lower quadriceps force (100°–130° flexion), increased anterior movement of the tibia (rollback), greater external tilt of the patella, and increasing facet pressure in the Vega PS design indicate a multifactorial cause for a higher rate of secondary resurfacing which was found in the EPRD patient cohort and might be related to the PS’ principle function.

Midarch Foot Pain: Entrapment Neuropathy of the Distal Medial Plantar Nerve and Its Branches.

Medial forefoot pain, or midarch pain, is usually attributed to plantar fasciitis. The authors present their findings of a previously unreported nerve entrapment of the medial proper plantar digital nerve (MPPDN). Ten fresh-frozen cadaveric specimens were analyzed for anatomical variance in the nerve distribution of the MPPDN. In addition, clinical results from a retrospective review of nine patients who underwent surgical nerve decompression of the MPPDN are presented. Significant anatomical variance was found for the MPPDN in the cadaveric dissection of 10 fresh-frozen specimens. Nine patients with a clinical diagnosis of entrapment of the MPPDN all obtained excellent pain relief with surgical external neurolysis. Only one complication occurred: a hypertrophic scar formation that was successfully treated with intralesional steroid injections. The authors believe that this MPPDN entrapment is often overlooked or misdiagnosed as plantar fasciitis. Surgical peripheral nerve decompression of this nerve can provide positive outcomes for patients suffering from midarch foot pain caused by this pain generator.

Respond of the different human cranial bones to pin-type head fixation device

BackgroundAt this juncture, there is no consensus in the literature for the use and the safety of pin-type head holders in cranial procedures.MethodsThe present analysis of the bone response to the fixation of the instrument provides data to understand its impact on the entire skull as well as associated complications. An experimental study was conducted on fresh-frozen human specimens to analyze the puncture hole due to the fixation of each single pin of the pin-type head holder. Cone-beam CT images were acquired to measure the diameter of the puncture hole caused by the instrument according to several parameters: the pin angle, the clamping force, and different neurosurgical approaches most clinically used.ResultsThe deepest hole, 2.67 ± 0.27 mm, was recorded for a 35° angle and a clamping force of 270 N at the middle fossa approach. The shallowest hole was 0.62 ± 0.22 mm for the 43° angle with a pinning force of 180 N in the pterional approach. The pterional approach had a significantly different effect on the depth of the puncture hole compared with the middle fossa craniotomy for 270 N pinning at 35° angle. The puncture hole measured with the 43° angle and 180 N force in prone position is significantly different from the other approaches with the same force.ConclusionsThese results could lead to recommendations about the use of the head holder depending on the patient’s history and cranial thickness to reduce complications associated with the pin-type head holder during clinical applications.

Partial Distal Biceps Avulsion Results in a Significant Loss of Supination Force.

Partial avulsions of the short and/or long head of the distal biceps tendon cause pain and loss of strength. The goal of the present study was to quantify the loss of supination and flexion strength following a series of surgical releases designed to simulate partial and complete short and long head traumatic avulsions. Mechanical testing was performed to measure supination moment arms and flexion force efficiency on 18 adult fresh-frozen specimens in pronation, neutral, and supination. The distal biceps footprint length was divided into 4 equal segments. In 9 specimens (the distal-first group), the tendon was partially cut starting distally by releasing 25%, 50%, and 75% of the insertion site. In the other 9 specimens (the proximal-first group), the releases started proximally. Mechanical testing was performed before and after each release. Significant decreases in the supination moment arm occurred after a 75% release in the distal-first release group; the decrease was 24% in pronation (p = 0.003) and 10% in neutral (p = 0.043). No significant differences in the supination moment arm (p ≥ 0.079) or in flexion force efficiency (p ≥ 0.058) occurred in the proximal-first group. A simulated complete short head avulsion significantly decreased the supination moment arm and therefore supination strength. A mechanical case can be made for repair of partial distal biceps tendon avulsions when the rupture involves ≥75% of the distal insertion site.

The posterior fibulotalocalcaneal ligament complex: a forgotten ligament

PurposeThe purpose of the present anatomical study was to define the exact morphology of the posterior fibulotalocalcaneal ligament complex (PFTCLC), both for a better orientation and understanding of the anatomy, especially during hindfoot endoscopy.MethodsTwenty-three fresh frozen specimens were dissected in order to clarify the morphology of the PFTCLC.ResultsIn all specimens, the ligament originated from the posteromedial border of the lateral malleolus between the posterior tibiofibular ligament (superior border) and the calcaneofibular ligament (CFL), (inferior border). This origin functions as the floor for the peroneal tendon sheath. The origin of the PFTCLC can be subdivided into two parts, a superior and inferior part. The superior part forms an aponeurosis with the superior peroneal retinaculum and the lateral septum of the Achilles tendon. From this structure, two independent laminae can be identified. The inferior part of the origin has no role in the aponeurosis and ligamentous fibres run obliquely to insert in the lateral surface of the calcaneus, in the same orientation as the CFL, but slightly more posterior, which was a consistent finding in all examined specimens. The PFTCLC is maximally tensed with ankle dorsiflexion and is located within the fascia of the deep posterior compartment of the leg.ConclusionsThe PFTCLC is part of the normal anatomy of the hindfoot and therefore should be routinely recognized and partly released to achieve access to the posterior ankle anatomical pathology, relevant for hindfoot endoscopy. The origin of the ligament complex forms the floor for the peroneal tendon sheath. The superior part of the origin plays a role in the formation of an aponeurosis with the superior peroneal retinaculum and the lateral septum of the Achilles tendon.

Endoscopic maxillectomy: anatomo-radiological description of the “double” maxillary sinus window

To present a modified endoscopic medial maxillectomy (MEMM) approach to control maxillary sinus pathologies. MEMM was completed in 13 fresh-frozen specimens. An MEMM includes cutting the nasolacrimal duct, inferior meatus flap, and repositioning the inferior turbinate (IT). The following measurements were obtained: length of IT, height from the nasal floor to valve of Hasner, height of the IT at the level of valve of Hasner, height of the IT at the insertion of the middle turbinate, and distance from the piriform aperture to the posterior wall of maxillary sinus and to the posterior border of palatine bone. Similar measurements were also performed on craniofacial computed tomography (CT) scans (n = 50). The surgical technique was performed in a case series (n = 8). The mean of the specimens was 82 (range 70–95) years old. The average area of the harvested inferior meatus flap area was 9.6 ± 1.0 cm2. In the radiologic study, the mean maximum antrostomy area was 8.8 ± 1.7 cm2 and the IT area overlapping the antral window was 5.8 ± 1.1 cm2, the area allowing a double window control was 3.1 ± 1.9 cm2, the posterior IT insertion length was 0.7 ± 0.4 cm, and the inferior meatus flap covering the inferior meatotomy had an area measuring 6.7 ± 1.7 cm2. Eight patients underwent MEMM for various benign conditions showing no recurrence after 26 month follow-up. The proposed modifications of MEMM provide a “double” window maxillary sinus control with access to all maxillary walls and preservation of the IT.

Accuracy and technical limits of percutaneous pedicle screw placement in the thoracolumbar spine.

The two-dimensional fluoroscopic method of percutaneous pedicle screw instrumentation has been clinically described as reliable method in the caudal thoracic and lumbosacral spine. Its accuracy has not been clearly reported in the cranial thoracic spine. The aim of this in vitro study was to investigate percutaneous pedicle screw placement accuracy according to pedicle dimensions and vertebral levels. Six fresh-frozen human specimens were instrumented with 216 screws from T1 to S1. Pedicle isthmus widths, heights, transversal pedicles and screws were measured on computed tomography. Pedicle cortex violation ≥ 2mm was defined as screw malposition. The narrowest pedicles were at T3-T5. A large variability between transversal pedicle axes and percutaneous pedicle screw was present, depending on the spinal level. Screw malposition rates were 36.1% in the cranial thoracic spine (T1-T6), 16.7% in the caudal thoracic spine (T7-T12), and 6.9% in the lumbosacral spine (L1-S1). The risk for screw malposition was significantly higher at cranial thoracic levels compared to caudal thoracic (p = 0.006) and lumbosacral (p < 0.0001) levels. Cortex violation ≥ 2mm was constantly present if the pedicle width was < 4.8mm. Percutaneous pedicle screw placement appears safe in the caudal thoracic and lumbosacral spine. The two-dimensional fluoroscopic method has a limited reliability above T7 because of smaller pedicle dimensions, difficulties in visualizing radiographic pedicle landmarks and kyphosis.

The moment arms and leverage of the human finger muscles

The moment arm of a muscle’s force represents the muscle’s leverage or mechanical advantage in producing a joint moment. It is indicative of the muscle’s potential to contribute to actuation of a joint in a particular joint motion direction and defines the role of the muscle, for example, as a joint flexor or abductor. The aims of this study were, firstly, to measure the moment arms of the flexor and extensor muscles of the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints, and the moment arms of the major abductor and adductor muscles of the metacarpophalangeal (MCP) joint of each finger in the hand; secondly, to assess the effect of change in joint angle on these moment arms; and thirdly, to determine if there are differences in a given flexor or extensor’s muscle moment arms between the joints it spans on a given finger, and across its tendon slips to multiple fingers. The tendon-excursion method was used to measure instantaneous muscle moment arms in nine fresh-frozen entire forearm cadaver specimens. Joint flexion angle was found to have significant effects on the moment arms of the extensor muscles at the MCP and PIP joints (p < 0.05). In contrast, the digital flexor muscles maintained relatively constant moment arms through the range of joint flexion. The moment arms of the digital flexors and extensors spanning multiple joints in a finger were largest at the MCP joints and smallest at the DIP joints. The findings demonstrate greater torque generating capacity for tasks such as grasping at the proximal interphalangeal joints, and smaller torque capacity for finer movement control at the distal interphalangeal joints. The dataset generated in this study may be useful in the development and validation of computational models used in surgical planning, and rehabilitation.

Biomechanical Comparison of Different Volar Screw Placements for Horizontal Oblique Scaphoid Fractures

Recently, some surgeons reported that most scaphoid waist fractures were horizontal oblique and not transverse in orientation. Therefore, this cadaveric study aimed to biomechanically compare fixation strength between central and eccentric screw placements for the volar fixation of this most common scaphoid waist fracture. Eight matched pairs of fresh-frozen forearm cadaver specimens were prepared for testing and randomly assigned to two groups: group I specimens were fixed by screws in a central placement, and group II specimens were fixed by screws in an eccentric placement. Horizontal oblique osteotomy was performed along the scaphoid waist. Then, each specimen was placed under the increasing load of a pneumatically driven plunger. We recorded stiffness, load to failure, and failure mechanisms between the central and eccentric screw placement groups. Stiffness was higher in central screw placement (74.1 N/mm) than in eccentric screw placement (29.39 N/mm). The median loads to failure in groups I and II were 54.14 and 26.22 N, respectively. In this biomechanical model, we demonstrated that central screw placement is superior to eccentric placement in terms of fixation strength. However, further clinical investigation is warranted to evaluate whether the different screw placements for volar approach of horizontal oblique scaphoid fractures affect the clinical outcomes.

Decreased prolyl hydroxylase 3 mRNA expression in oncocytomas compared with clear cell renal cell carcinoma.

Hypoxia inducible factors (HIF) and prolyl hydroxylase domain (PHD) enzymes play a central role in tumor progression in clear cell renal cell carcinoma (ccRCC). However, there are currently no data regarding the behavior of this pathway (HIF/PHD) in a large number of benign renal tumors, the oncocytomas. The aim of the present study was to compare the expression levels of these factors between ccRCC and oncocytoma tumors. A total of 56 fresh frozen specimens from patients with ccRCC and 14 oncocytoma specimens were analyzed via reverse transcription-quantitative polymerase chain reaction in order to assess the expression levels of HIF-1α, HIF-2α, PHD1, PHD2, and PHD3. The analysis involved both fresh frozen tumor samples as well as adjacent normal kidney tissues. In ccRCC, HIF-1α and HIF-2α levels were upregulated in 65.5% and 71.4% of cases, respectively. PHD3 was downregulated only in 15.4% of the ccRCC cases, in contrast with oncocytoma cases, which exhibited low expression levels in the majority. The upregulation of PHD3 messenger RNA (mRNA) levels in ccRCC when compared with oncocytoma was statistically significant (P<0.001). No other comparisons (HIF-1α, HIF-2α, PHD1, and PHD2) were significantly different. HIF-2α and PHD3 mRNA expression levels were negatively correlated with Fuhrman Grade (P=0.029 and P=0.026, respectively) in ccRCC. To the best of our knowledge, this is the first time that the HIF/PHD pathway was compared between ccRCC and a common benign tumor, identifying the upregulation of PHD3 as the possible underlying factor guiding the difference in the behavior of ccRCC.