Dorsal Collapse Research Articles

Evaluating the efficiency of endoscope-assisted septo-rhinoplasty via intranasal approach

Objective: To observe the functional and esthetic results of endoscope-assisted septo-rhinoplasty via intranasal approach. Methods: The clinical data of 12 patients with septal deviation and nasal deformity in the University of Hong Kong-Shenzhen Hospital from June 2021 to June 2022 were analyzed, including 8 males and 4 females, aging 28 to 58 years. All patients were operated under general anesthesia. The septal deviation was corrected by hemitransfixion incision, combined with intercartilaginous incision and other intranasal or extranasal incisions to perform osteotomy, hump resection and saddle nose correction. Patient satisfaction with postoperative functional and aesthetic improvements was assessed through Nasal Obstruction Symptom Evaluation (NOSE), Rhinoplasty Outcome Evaluation (ROE), and Visual Analogue Scale (VAS).SPSS 25 software was used for statistical analysis. Results: The correction of nasal septum deviation was satisfactory in all 12 patients. Nasal obstruction was relieved, with NOSE score and VAS score of nasal ventilation decreased [(21.67±10.30) vs (70.83±14.12), (1.83±1.03) vs (8.33±0.89), t value was 9.49 and 16.30, respectively, both P<0.05]. The nasal appearance of 10 patients with crooked nose deformity was improved, with ROE score and VAS score of nasal appearance increased [(21.30±2.31) vs (8.10±3.31), (8.90±0.99) vs (3.80±1.62), t value was -11.85 and -9.33, respectively, both P<0.05];The nasal vestibule morphology of 2 patients with abnormal nasal vestibule was improved. During the follow-up of 12 to 24 months, no postoperative complication such as nasal septum perforation, nasal cavity adhesion or nasal dorsal collapse occurred in all patients. Conclusion: Endoscope-assisted septo-rhinoplasty via intranasal approach can resolve both functional and esthetic problems at the same time, improving outcomes while reducing surgical trauma.

Lung perfusion during veno-venous extracorporeal membrane oxygenation in a model of hypoxemic respiratory failure

BackgroundVeno-venous extracorporeal membrane oxygenation (ECMO) provides blood oxygenation and carbon dioxide removal in acute respiratory distress syndrome. However, during ECMO support, the native lungs still play an important role in gas exchange, functioning as a second oxygenator in series with ECMO. The hypoxic vasoconstriction mechanism diverts regional blood flow within the lungs away from regions with low oxygen levels, optimizing ventilation/perfusion matching. ECMO support has the potential to reduce this adaptive pulmonary response and worsen the ventilation/perfusion mismatch by raising venous oxygen partial pressure. Thus, the objective of this study was to evaluate the effect of ECMO on regional pulmonary perfusion and pulmonary hemodynamics during unilateral ventilation and posterior lung collapse.MethodsFive Agroceres pigs were instrumented, monitored and submitted to ECMO. We used the Electrical Impedance Tomography (EIT) to evaluate lung ventilation and perfusion in all protocol steps. Effects of ECMO support on pulmonary hemodynamics and perfusion involving two different scenarios of ventilation/perfusion mismatch: (1) right-lung selective intubation inducing collapse of the normal left lung and (2) dorsal lung collapse after repeated lung lavage. Data including hemodynamics, respiratory, lung perfusion/ventilation, and laboratory data over time were analyzed with a mixed generalized model using the subjects as a random factor.ResultsThe initiation of ECMO support provided a significant reduction in Mean Pulmonary Artery Pressure (PAPm) in both situations of ventilation/perfusion mismatch. However, distribution of lung perfusion did not change with the use of ECMO support.ConclusionsWe found that the use of ECMO support with consequent increase in venous oxygen pressure induced a significant drop in PAPm with no detectable effect on regional lung perfusion in different scenarios of ventilation/perfusion mismatch.

Analysis of clinical effect of nasal endoscope-assisted nasal columella approach for simultaneous correction of nasal septum deviation and crooked nose deformity

Objective:To analyze the clinical effect of nasal endoscope-assisted nasal columella approach in the correction of nasal septum deviation and crooked nose deformity. Methods:The clinical data of 33 patients with deviation of nasal septum with crooked nose deformity in First Affiliate Hospital of Air Force Military Medical University from January 2016 to June 2019 were collected. All patients underwent surgery under general anesthesia. Nasal columella inverted "V" incision was used to expose and release. The deviated nasal septum cartilage and bone were removed with the assistance of nasal endoscope. Twelve（36.4%） patients underwent osteotomy of nasal bone and frontal process of maxilla at the same time, 13（39.4%） patients used autologous nasal septum to reshape the tip, back and external nose. Results:During a follow-up of 18 months to 60 months, 30（90.9%） patients were satisfied with the improvement of postoperative nasal function, 3（9.1%） patients were basically satisfied; 23（69.7%） patients were satisfied with the appearance of the nose after operation, 8（24.2%） patients were basically satisfied, and 2（6.1%） patients were dissatisfied. No postoperative complications such as nasal adhesion, nasal septum perforation, nasal septum hematoma and nasal dorsal collapse occurred in all patients. Conclusion:The nasal endoscope-assisted nasal columella approach and the correction of nasal septum deviation and crooked nose deformity can solve the nasal deformity and nasal ventilation function at the same time, realize the unity of cosmetology and function, and reduce the frequency and cost of surgical treatment at the same time. The effect is good, and the patients benefit greatly.

Upper Oesophageal Sphincter Aplasia in Equids: Observations in Preoperative Patients and a Possible Association with some Cases of Dorsal Pharyngeal Collapse and Paradoxical Sleep Deprivation

Upper Oesophageal Sphincter Aplasia in Equids: Observations in Preoperative Patients and a Possible Association with some Cases of Dorsal Pharyngeal Collapse and Paradoxical Sleep Deprivation

Vertebral Fractures Due to Metastatic Tumors: A Case Report

Metastasis is responsible for most cancer-related morbidity and mortality. In principle, metastasis is the spread of cancer from the primary site to distant tissues. Pathological consistency may be compromised during metastasis. We report the case of a 55-year-old man with MRI images of the dorsal spine showing the effects of a fifth dorsal collapse. He was referred to our hospital because of back pain, imbalance, inability to walk, and weakness of the lower limb. The histological features of bone tumors were corresponding with cell carcinoma, and bone damage was considered metastatic from a site in the lung. His general situation gently diminished, and He died during radiotherapy.

Evaluation of regional ventilation by electric impedance tomography during percutaneous dilatational tracheostomy in neurocritical care: a pilot study

BackgroundPercutaneous dilatational tracheostomy (PDT) has become a widely performed technique in neurocritical care, which is however known to be accompanied by some risks to the patient. The aim of this pilot study was to assess the derecruitment effects of PDT with the electric impedance tomography (EIT) during the PDT procedure in neurocritical care.MethodsThe prospective observational pilot study investigated 11 adult, intubated, mechanically ventilated patients with acute brain disease. We recorded EIT data to determine regional ventilation delay standard deviation (RVD SD), compliance win (CW) and loss (CL), end-expiratory lung impedance (EELI), with the EIT belt placed at the level of Th 4 before, during and after the PDT, performed in the standard PDT position ensuring hyperextension of the neck.ResultsFrom 11 patients, we finally analyzed EIT data in 6 patients - EIT data of 5 patients have been excluded due to the insufficient EIT recordings. The mean RVD SD post-PDT decreased to 7.00 ± 1.29% from 7.33 ± 1.89%. The mean post-PDT CW was 27.33 ± 15.81 and PDT CL 6.33 ± 6.55. Only in one patient, where the trachea was open for 170 s, was a massive dorsal collapse (∆EELI − 25%) detected. In other patients, the trachea was open from 15 to 50 s.ConclusionsThis pilot study demonstrated the feasibility of EIT to detect early lung derecruitment occurring due to the PDT procedure. The ability to detect regional changes in ventilation could be helpful in predicting further progression of ventilation impairment and subsequent hypoxemia, to consider optimal ventilation regimes or time-schedule and type of recruitment maneuvres required after the PDT.

Evaluating the necessity of bone augmentation for distal radius fracture fixed with a volar locking plate: a retrospective study

BackgroundMultiple approaches for fixation of distal radius fractures exist; nonetheless, there is no consensus on the optimal treatment for these injuries. Although using volar locking plates has become increasingly common as a surgical intervention, the usefulness of bone augmentation remains debatable. Therefore, this study aimed to evaluate the necessity of bone augmentation for distal radius fractures fixed with a volar locking plate.MethodsThis retrospective study enrolled patients with a single distal radius fracture treated with a volar locking plate between January 2014 and December 2016. Overall, 105 fractures were included and divided into two groups (non-bone augmentation: group 1, n = 88; bone augmentation: group 2, n = 17). Images were reviewed, and dorsal cortex collapse, volar tilting, and radial height and inclination were measured immediately after surgery and at the 6-month follow-up.ResultsBoth groups exhibited significant differences in dorsal collapse (p < 0.001 and p = 0.001, respectively) and radial height shortening (p < 0.001 and p = 0.039, respectively); volar tilting and radial inclination did not differ significantly. There was no difference in the degree of dorsal collapse (p = 0.715) and radial height shortening (p = 0.651) between the two groups. Of the 105 fractures, 54 were identified as comminuted type according to the AO classification (A3, C2, and C3), and similar radiographic outcomes were noted.ConclusionsVolar locking plates for the treatment of distal radius fractures with or without bone augmentation do not affect the radiographic outcomes. In comminuted fractures, additional bone augmentation is unnecessary if intraoperative anatomical reduction and fixation are performed when possible.

Crumbs2 mediates ventricular layer remodelling to form thespinal cord central canal.

In the spinal cord, the central canal forms through a poorly understood process termed dorsal collapse that involves attrition and remodelling of pseudostratified ventricular layer (VL) cells. Here, we use mouse and chick models to show that dorsal ventricular layer (dVL) cells adjacent to dorsal midline Nestin(+) radial glia (dmNes+RG) down-regulate apical polarity proteins, including Crumbs2 (CRB2) and delaminate in a stepwise manner; live imaging shows that as one cell delaminates, the next cell ratchets up, the dmNes+RG endfoot ratchets down, and the process repeats. We show that dmNes+RG secrete a factor that promotes loss of cell polarity and delamination. This activity is mimicked by a secreted variant of Crumbs2 (CRB2S) which is specifically expressed by dmNes+RG. In cultured MDCK cells, CRB2S associates with apical membranes and decreases cell cohesion. Analysis of Crb2F/F/Nestin-Cre+/- mice, and targeted reduction of Crb2/CRB2S in slice cultures reveal essential roles for transmembrane CRB2 (CRB2TM) and CRB2S on VL cells and dmNes+RG, respectively. We propose a model in which a CRB2S-CRB2TM interaction promotes the progressive attrition of the dVL without loss of overall VL integrity. This novel mechanism may operate more widely to promote orderly progenitor delamination.

Multiple steps characterise ventricular layer attrition to form the ependymal cell lining of the adult mouse spinal cord central canal.

The ventricular layer of the spinal cord is remodelled during embryonic development and ultimately forms the ependymal cell lining of the adult central canal, which retains neural stem cell potential. This anatomical transformation involves the process of dorsal collapse; however, accompanying changes in tissue organisation and cell behaviour as well as the precise origin of cells contributing to the central canal are not well understood. Here, we describe sequential localised cell rearrangements which accompany the gradual attrition of the spinal cord ventricular layer during development. This includes local breakdown of the pseudostratified organisation of the dorsal ventricular layer prefiguring dorsal collapse and evidence for a new phenomenon, ventral dissociation, during which the ventral‐most floor plate cells separate from a subset that are retained around the central canal. Using cell proliferation markers and cell‐cycle reporter mice, we further show that following dorsal collapse, ventricular layer attrition involves an overall reduction in cell proliferation, characterised by an intriguing increase in the percentage of cells in G1/S. In contrast, programmed cell death does not contribute to ventricular layer remodelling. By analysing transcript and protein expression patterns associated with key signalling pathways, we provide evidence for a gradual decline in ventral sonic hedgehog activity and an accompanying ventral expansion of initial dorsal bone morphogenetic protein signalling, which comes to dominate the forming the central canal lining. This study identifies multiple steps that may contribute to spinal cord ventricular layer attrition and adds to increasing evidence for the heterogeneous origin of the spinal cord ependymal cell population, which includes cells from the floor plate and the roof plate as well as ventral progenitor domains.

Incidence of Odontocetes with Dorsal Fin Collapse in Maui Nui, Hawaii

Incidence of Odontocetes with Dorsal Fin Collapse in Maui Nui, Hawaii

Biomechanical Assessment of the Dorsal Spanning Bridge Plate in Distal Radius Fracture Fixation: Implications for Immediate Weight-Bearing.

The goal of this study was to compare the biomechanical stability of a 2.4-mm dorsal spanning bridge plate with a volar locking plate (VLP) in a distal radius fracture model, during simulated crutch weight-bearing. Five paired cadaveric forearms were tested. A 1-cm dorsal wedge osteotomy was created to simulate an unstable distal radius fracture with dorsal comminution. Fractures were fixed with a VLP or a dorsal bridge plate (DBP). Specimens were mounted to a crutch handle, and optical motion-tracking sensors were attached to the proximal and distal segments. Specimens were loaded in compression at 1 mm/s on a servohydraulic test frame until failure, defined as 2 mm of gap site displacement. The VLP construct was significantly more stable to axial load in a crutch weight-bearing model compared with the DBP plate (VLP: 493 N vs DBP: 332 N). Stiffness was higher in the VLP constructs, but this was not statistically significant (VLP: 51.4 N/mm vs DBP: 32.4 N/mm). With the crutch weight-bearing model, DBP failed consistently with wrist flexion and plate bending, whereas VLP failed with axial compression at the fracture site and dorsal collapse. Dorsal spanning bridge plating is effective as an internal spanning fixator in treating highly comminuted intra-articular distal radius fracture and prevents axial collapse at the radiocarpal joint. However, bridge plating may not offer advantages in early weight-bearing or transfer in polytrauma patients, with less axial stability in our crutch weight-bearing model compared with volar plating. A stiffer 3.5-mm DBP or use of a DBP construct without the central holes may be considered for distal radius fractures if the goal is early crutch weight-bearing through the injured extremity.

Open Reduction and Volar Plate Fixation of Dorsally Displaced Distal Radius Fractures: A Prospective Study of Functional and Radiological Outcomes.

The fractures of the distal radius have always posed a unique challenge to the orthopaedic fraternity. The complex ligamentous and bony anatomy offers a wide variety of fractures to be dealt with around this zone. Over the years these injuries have become common especially in the elderly age group as well as the implants and surgical techniques have improved. To assess the radiological and functional outcome after fixation of intra-articular dorsally displaced distal radius fractures with open reduction and volar Locking Compression Plate fixation (LCP). To study the complications occurring with this technique. A prospective study was conducted in the Department of Orthopaedics at ARS Hospital, Tirupur, Tamil Nadu, from June 2015 to June 2016. A total of 20 skeletally mature patients with Lidstrom class 2D and 2E fresh closed distal radius fractures were enrolled in the study. All the patients underwent open reduction with locking compression plating with titanium LCPs using the volar approach. The patients were reviewed regularly at three, six, 12 and 24 weeks. Final assessment of radiographic fracture union was done and scored as per the 'Radiographic Scoring System to Evaluate Union of Distal Radius Fractures {Radius Union Scoring System (RUSS)}' and the functional assessment of the wrist was done using the Mayo wrist score. The final results were tabulated and calculated statistically using 'frequency and proportions' and 'Chi-square tests' were used to assess the test of association. Of the 20 patients reviewed, one patient had excellent Mayo wrist score, five had good scores, 12 had satisfactory and two patients had poor results. Seven patients had a RUSS score less than five points and four patients had RUSS score of five points, four patients had six points, two patients had seven points and three patients had eight points. One patient was noted to have dorsal collapse of the fracture during the final review. But, no evident of cosmetic deformity or any diminution in functional outcome of wrist was noted. Open reduction and internal fixation with volar plating of dorsally displaced intra-articular distal radius fractures is an excellent technique with acceptable radiological fracture union and satisfactory functional outcome of the wrist.

A novel method for nasal dorsal reconstruction: permanent fixation using Kirschner wire-guided hidden sutures.

In this study, we aimed to present a novel application and use of Kirschner wire-guided suturing that is less invasive and allows permanent fixation for nasal dorsal reconstruction. A total of 23 patients, who underwent surgery between 2009 and 2013, were included in this study: 19 with saddle nose deformity and 4 patients with keystone area damage, or collapse of the dorsal nasal support during primary septoplasty or rhinoplasty. The patients were asked to fill out a nasal obstruction symptom evaluation (NOSE) scale preoperatively and at the postoperative sixth month to assess breathing quality. The patients were followed up for complications such as nasal dorsal contour irregularity, dorsal collapse, as well as graft malposition and infections. The results of the surgeries were assessed on the basis of preoperative and postoperative examinations, septal support test, NOSE scale results, and photographic comparison. The mean (SD) NOSE scales were 78.91 (10.09) and 30.48 (10.71) in the preoperative and postoperative periods, respectively. The difference of mean NOSE scale was statistically significant (P < 0.001). None of the patients experienced nasal dorsal collapse or graft malposition. Two patients had nasal dorsal irregularity complaints owing to inadequate costal cartilage edge beveling. None of the patients had complications of suture reaction, suture visibility, or suture extrusion. All of the patients stated that they were happy with the cosmetic outcome. Permanent sutures introduced through channels made with the Kirschner wire provide a less invasive, cosmetically pleasing, and functional solution, promising more reliable results in the long term.

Third tarsal bone fractures in the greyhound

To describe the signalment, morphology, response to treatment and prognosis of third tarsal bone fractures in the racing greyhound. All third tarsal bone fractures seen by the author over a ten year period were included in the study. Diagnosis was by radiography. Treatments were reconstruction with a lag screw, fragment removal, centrodistal joint arthrodesis or conservative management. Twenty-three cases were included in the study of which 16 cases were recent and seven cases chronic fractures. The chronic cases had been rested from between three and six months before an examination for recurrent lameness. There were five concomitant second tarsal bone fractures. Partial dorsal collapse was present in four cases. Thirteen dogs had lag screw fixation; three were lost to follow-up, seven returned to racing and three, all with partial tarsal collapse, failed to return to racing. Two dogs that had a centrodistal joint arthrodesis and one dog treated by rest alone raced again. Two dogs that had fragment removal failed to return to racing. Veterinary examination of greyhounds with third tarsal bone fractures is often not sought at the time of the initial injury due to the benign presenting signs. Recurrence of lameness after rest is common. The prognosis for a successful return to racing would appear to be good following fragment fixation in both acute and chronic cases without dorsal tarsal collapse. Centrodistal joint arthrodesis may encourage bone union. The prognosis for conconservatively treated cases is guarded. Fragment removal is not recommended as a treatment.

Management of soft-tissue trauma to the face

The management of acute soft-tissue trauma can be very challenging for the facial plastic surgeon. The goals of management of facial trauma are the preservation of form and function. These goals are particularly important in facial soft-tissue trauma, where injuries can cause not only esthetic deformities but also can affect neural function, normal mastication, visual fields, and salivary outflow. This article outlines the evaluation and treatment of acute soft-tissue facial trauma. The key components include allowing for the stabilization of the patient, complete examination of the injury and face, thorough wound irrigation and debridement of necrotic tissue, preservation of all viable tissue, tension-free closure, and realignment of important facial esthetic structures. Special consideration must be given to injuries of functional structures such as the facial nerve, ductal systems or organs, and ensuring appropriated management of these structures.

The structure and stratigraphy of SE Zanskar, Ladakh Himalaya

A field study of over 4 km thickness of Cambro-Ordovician to Cretaceous sediments deposited on the passive margin of northern India has provided significant new data on the thickness, age and depositional environments of these deposits. The first detailed structural map of the Phuctal area and a regional map of Eastern Zanskar are presented, together with sequentially restored structural cross sections. An imbricate thrust duplex and a lateral ramp stack, which formed in the Phuctal area during SW-directed thrust propagation, were later deformed by NE-directed structures probably produced during gravitational collapse of the thrust stack. Collapse occurred along the previously documented Zanskar shear zone, and also by reactivation of the basal detachment of the Zangla nappe. This dorsal collapse of the orogen was probably related to an increase in uplift rate during the Neogene, and may have coincided with the initiation of the Main Boundary Thrust farther south.

Midcarpal instability caused by malunited fractures of the distal radius

Thirteen patients with malunited fractures of the distal radius developed symptoms of pain and instability of the midcarpal joint. In six cases, a recurrent voluntary midcarpal subluxation was also present during ulnar deviation. These symptoms were first noticed several weeks, and at times several months, after all immobilization for the treatment of the original fracture had been discontinued. We believe that the loss of the normal palmar tilt of the distal articular surface of the radius prepositions the carpus in a dorsal collapse alignment, which enables this instability to develop. Although the instability is localized to the midcarpus , it is treated best, in our opinion, by a corrective osteotomy of the distal radius. In nine patients, osteotomies resulted in relief of preoperative symptoms and correction of midcarpal instability. In one patient, osteotomy of the radius was deemed unnecessary because the loss of palmar tilt of the radius was minimal. Instead the midcarpal ( triquetrohamate ) joint was stabilized by ligament reconstruction. Only transient correction was obtained, with later recurrence of the voluntary midcarpal subluxation.