Reconstruction of deep and perforating corneal defects in dogs-A review (Part I/III): Autogenous ocular tissues, donor tissues, and corneal clarity scoring.

Corneal reconstruction is a key part of veterinary ophthalmic practice and numerous reconstructive techniques have been described for use in small animals in the peer-reviewed veterinary literature written in English. Despite the evidence accrued over the last six decades in over 40 clinical articles and numerous other publications on ocular surface health, several key areas require further study. The comparison between studies is difficult due to elements that go beyond common factors, such as the indication for surgery, the reconstructive technique preferred by the surgeon or the availability of reconstructive materials. However, the differences in reporting style adopted by different authors between similar studies and the lack of data found in retrospective studies add to this complexity. The present review is divided into three parts. One covers the use of autologous materials for reconstruction and corneal transplants, as well as corneal clarity. A second part focuses on biomaterials and keratoprosthetics, while the third part focuses on the use of corneal sutures and report of ocular discomfort/pain in the veterinary literature. The review focuses on the main findings of each reconstruction technique. It aims to identify areas where key information about common procedures is missing so that general guidelines may be provided for the planning of patient record keeping and future retrospective or prospective studies, while it also aims to highlight the presence of knowledge gaps that deserve further attention.

STABILITY OF MEDIALLY AND LATERALLY MALPOSITIONED SCREWS: A BIOMECHANICAL STUDY ON CADAVERS.

BACKGROUND CONTEXT: Pedicle screw instrumentation is widely used in spine surgery. Axial screw misplacement is a common complication. In addition to the recognized neurovascular risks associated with screw misplacement, the biomechanical stability of misplaced screws remains a subject of debate. PURPOSE: The present study investigates whether screw misplacement in the lumbar spine reduces mechanical screw hold. STUDY DESIGN/SETTING: Cadaveric biomechanical study METHODS: Pedicle screw (mis)placement was planned for 12 fresh frozen cadaveric spines between the T12 and the L5 levels. The screws were then implanted into the vertebrae with the help of 3D-printed template guides. Pre- and post-instrumentation computed tomography (CT) scans were acquired for instrumentation planning and quantification of the misplacement. The instrumented vertebrae were potted into CT transparent boxes using Polymethyl methacrylate and mounted on a standardized biomechanical setup for pull-out (PO) testing with uniaxial tensile load. RESULTS: The bone density of all the specimens as per HU was comparable. The predicted pull-out force (POF) for screws medially misplaced by 2mm, 4mm, and 6mm was respectively 985 N (SD 474), 968 N (SD 476) and 822 N (SD 478). For screws laterally misplaced by 2mm, 4mm, and 6mm the POF was respectively 605 N (SD 473), 411 N (SD 475), and 334 N (SD 477). Screws that did not perforate the pedicle (control) resisted pull-out forces of 837 N (SD 471). CONCLUSIONS: Medial misplacement is associated with increased axial screw hold against static loads compared to correctly placed screws and laterally placed screws. CLINICAL SIGNIFICANCE: In clinical settings, the reinsertion of medially misplaced screws should primarily aim to prevent neurological complications while the reinsertion of lateral misplaced screws should aim to prevent screw loosening.

Impact of landmark crater creation on improving accuracy of pedicle screw insertion in robot-assisted scoliosis surgery.

PURPOSE: This study evaluated the impact of the Landmark Crater (LC) method on pedicle perforation rates in robot-guided surgery for pediatric scoliosis for each pedicle diameter. METHODS: Seventy-six scoliosis patients underwent robot-assisted posterior spinal fusion. The cohort consisted of 19 male and 57 female patients, with a mean ± standard deviation age of 17.5 ± 7.7 years and a preoperative Cobb angle of 57.0 ± 18.5°. The LC method is a method in which craters that serves as a landmark are created in advance at the planned PS insertion site of all pedicles within the intraoperative CT imaging area. The patients were divided into the LC group, in which PS insertion was performed using the LC method, and the control group using the conventional PS insertion method. Overall and pedicle perforation rates for each pedicle outer diameter were compared between the groups by Fisher's exact test. RESULTS: The LC group exhibited a significantly lower pedicle major perforation rate than did the control group (2.7% vs. 6.2%, P = 0.001). The perforation rates in pedicles with a pedicle outer diameter > 6 mm, 4-6 mm, 2-4 mm, and < 2 mm were 0.61%, 1.6%, 5.1%, and 21%, in the LC group and 0.75%, 4.1%, 12%, and 50% in the control group, respectively. CONCLUSION: In robot-assisted surgery for pediatric scoliosis, the LC method enabled significantly lower pedicle perforation rates over the conventional method. Both the LC and conventional methods exhibited higher perforation rates for smaller pedicle diameters.

Spinal Cord Stimulator Implantation for Complex Regional Pain Syndrome in Patient With Extensive Vertebral Surgical History: A Case Report.

Spinal cord stimulation (SCS) has emerged as a novel therapeutic option for refractory complex regional pain syndrome (CRPS). However, SCS placement is often complicated by a prior history of surgical manipulation and hardware implantation along the spinal column. Through this case exploration, we aim to expand the technical approach to SCS implantation in CRPS and encourage further research into innovative approaches for this treatment modality. Our patient is a 61-year-old female with a past medical history of bilateral C7 cervical pedicle fracture status and extensive surgical manipulation, including cervical laminectomy and hardware placement along the cervical spine. The development of CRPS refractory to conventional therapies complicated her course. We obtained non-contrast computed tomography (CT) to confirm intact lamina in vertebral levels below C3 and proceeded with the SCS trial with successful lead placement up to C5. Despite prior surgical manipulation of the vertebral spine hindering our ability to access the ideal C2 level, we were able to achieve significant coverage up to the C5 level. Obtaining non-contrast CT preoperatively and carefully assessing the epidural space patency were integral to our ability to assess the feasibility of lead placement in a patient with extensive hardware. Through this approach, we are able to offer SCS to patients who would otherwise be precluded from this modality.

Neuro Navigation Versus Conventional Spinal Techniques in Analyzing Nerve Injury and Anatomical Accuracy: A Systematic Review.

Neuronavigation, a computer-assisted surgical technique, enhances the accuracy of spinal surgery by using medical imaging to guide the surgeon's instruments. This method mitigates the serious complications of screw misplacement, such as dural tears, nerve damage, vascular injuries, and internal organ damage, by integrating pre-operative imaging data with real-time intraoperative sensor readings. Because of this integration, it is possible to visualize the spine in three dimensions, guaranteeing accurate instrument placement and greatly lowering the risk of complications. Despite its growing popularity, the benefits of neuronavigation in spinal instrumentation are debated. While some studies report improved accuracy in pedicle screw placement, others find no significant difference compared to conventional freehand techniques. Further research is required to determine the long-term benefits of neuronavigation, including its impact on patient outcomes, like reduced pain and improved function. This systematic review will evaluate the evidence on the risks and benefits of neuronavigation in spinal instrumentation surgery, compared to conventional techniques.

Accuracy of Cervical Pedicle Screw Insertion With and Without a Navigation-Linked High-Speed Drill: A Retrospective Clinical Study.

INTRODUCTION: Cervical pedicle screw (CPS) fixation provides high stability but poses a risk of nerve and vascular injury. Although useful for reducing CPS deviation rates, navigation systems cannot completely eliminate deviation. This study aimed to compare two methods for creating insertion paths, one using a navigation-linked high-speed drill (NAVI drill) and the other using conventional manual probing. METHODS: Our study comprised 104 patients with 509 CPSs at the C3-6 level who were treated at our institution between 2017 and 2023. CPS deviations were graded according to the Neo classification system, and the deviation direction (medial, lateral, cranial, or caudal) was assessed. Complications associated with CPS deviation were also investigated. We compared cases that used the NAVI drill (Group M) with those that used manual probing (Group N). RESULTS: Group M included 45 cases (252 screws), and Group N included 59 cases (257 screws). The CPS deviation rate was grade 1 or higher in 14.7% and 17.1% of cases in Groups M and N, respectively (p = 0.469). It was grade 2 or higher in 1.2% and 4.3% of cases in Groups M and N, respectively (p = 0.222). The medial, lateral, caudal, and cranial deviation direction rates were 56.8%, 2.7%, 40.5%, and 0% in Group M and 13.6%, 72.7%, 11.4%, and 2.3% in Group N, respectively (p < 0.001). In one case in Group N, a grade 3 lateral deviation resulted in vertebral artery injury (VAI). CONCLUSIONS: The use of the NAVI drill was associated with a slightly lower, albeit insignificant, CPS deviation rate. However, it significantly lowered the proportion of lateral deviations. Therefore, the NAVI drill is a useful tool for preventing VAI.

Usefulness of using the superficial temporal pedicle as the recipient site for microvascular anastomosis in facial reconstruction: a retrospective study of 94 cases.

In cranio-cervico-facial reconstructive surgery, it is accepted that the use of free flaps is the treatment of choice. The multiple antecedents can place the surgeon in situations of vascular deserts. The aim of our study is to report and analyse our experience of the use of temporal vessels in primary and secondary reconstructive surgery. A retrospective study was conducted between 01/01/2010 and 31/03/2023. Patients who underwent cranio-cervico-facial reconstruction using free flaps, with use of the superficial temporal pedicle as the recipient site for the vascular anastomosis were included. Early and late complication and failure rates were analysed according to type of reconstruction, location and risk factors for free flap failure. A total of 94 patients underwent craniocervical-facial reconstruction using a free flap anastomosed to the superficial temporal pedicle (in primary or secondary situations). Ten patients underwent reconstruction of the upper third, 58 the middle third and 26 the lower third. With an overall complication rate of 28.7% (21.3% minor complications and 7.4% major complications). Our study proves the reliability of the superficial temporal pedicle, both in the primary situation (with a success rate of 93.9%) and in the secondary situation (with a success rate of 89.3%), as well as its versatility whatever the cranio-cervico-facial level to be reconstructed. This study demonstrates the value of preserving the superficial temporal pedicle in craniofacial reconstruction surgery. This is because it is a preferred recipient site for reconstructions of the upper and middle thirds in the primary situation or in the event of recourse.

Biomechanical Effects of a Novel Standalone Posterior Lumbar Facet Joint Stabilization Device: An In Vitro Cadaveric Study.

OBJECTIVE: Although pedicle screw and rod instrumentation remains the gold standard method of posterior rod fixation, it is associated with complications, including pedicle breach and facet joint violation. There is current interest in facet joint stabilization with the potential to create a less invasive, natural arch of fixation that may avoid the complications associated with pedicle screw and rod instrumentation. This study examined the stabilizing potential of a novel facet joint fixation device for single-level (L4-L5) fixation in a human cadaveric model. METHODS: Six L3-S1 specimens were tested multidirectionally under pure moment loading (7.5 Nm) in 3 conditions: 1) intact, 2) L4-L5 facet fixation without screws, and 3) L4-L5 facet fixation with screws. L4-L5 intervertebral disc angles were measured radiographically. Range of motion (ROM) and disc angles were compared using repeated-measures analysis of variance, with statistical significance set at P < 0.05. RESULTS: Compared with the intact condition, L4-L5 bilateral facet fixation without or with screw fixation significantly reduced L4-L5 angular ROM in all directions (P ≤ 0.003). No significant differences were observed in cranial and caudal adjacent-segment ROM (P ≥ 0.08) except for L3-L4 fixation in extension, which exhibited small motion increases (0.12° without screws, 0.1° with screws) versus the intact condition (P ≤ 0.003). No statistically significant differences were observed in disc angle values between the conditions (P = 0.87). CONCLUSIONS: Bilateral lumbar facet fixation with and without supplemental transfacet screw fixation provided significant stability. Cranial and caudal adjacent-level ROM was not influenced by facet fixation except for a slight increase in cranial segment motion during extension. Facet fixation did not alter the lordotic intervertebral disc angle at the instrumented level.

High Accuracy of Three-Dimensional Navigated Kirschner-Wire-Less Single-Step Pedicle Screw System (SSPSS) in Lumbar Fusions: Comparison of Intraoperatively Planned versus Final Screw Position.

(1) Background: Our team has previously introduced the Single-Step Pedicle Screw System (SSPSS), which eliminates the need for K-wires, as a safe and effective method for percutaneous minimally invasive spine (MIS) pedicle screw placement. Despite this, there are ongoing concerns about the reliability and accuracy of screw placement in MIS procedures without traditional tools like K-wires and Jamshidi needles. To address these concerns, we evaluated the accuracy of the SSPSS workflow by comparing the planned intraoperative screw trajectories with the final screw positions. Traditionally, screw placement accuracy has been assessed by grading the final screw position using postoperative CT scans. (2) Methods: We conducted a retrospective review of patients who underwent lumbar interbody fusion, using intraoperative 3D navigation for screw placement. The planned screw trajectories were saved in the navigation system during each procedure, and postoperative CT scans were used to evaluate the implanted screws. Accuracy was assessed by comparing the Gertzbein and Robbins classification scores of the planned trajectories and the final screw positions. Accuracy was defined as a final screw position matching the classification of the planned trajectory. (3) Results: Out of 206 screws, 196 (95%) were accurately placed, with no recorded complications. (4) Conclusions: The SSPSS workflow, even without K-wires and other traditional instruments, facilitates accurate and reliable pedicle screw placement.

Tips and tricks for using cement augmentation of pedicle screws and vertebral body replacements - a literature review supported by two case reports. / Consejos y trucos para el uso de cemento óseo en tornillos pediculares y reemplazos de cuerpos vertebrales: una revisión de la literatura respaldada por dos informes de casos.

BACKGROUND: The prevalence of osteoporosis is escalating alongside an aging global population, increasing the demand for spinal surgeries, including those necessitating cement augmentation for enhanced construct stability. OBJECTIVE: This article delves into the nuanced application of cement augmentation techniques for pedicle screws and vertebral body replacements (VBR), aimed at optimizing surgical outcomes in osteoporotic spines. METHOD: Drawing from a comprehensive literature review according to important clinical and biomechanical studies and the authors' clinical experiences, we elucidate strategies to mitigate complications and improve surgical efficacy. RESULTS: Cement augmentation has shown promise in managing vertebral fractures and in securing pedicle screws within osteoporotic vertebrae, with the advent of polymethylmethacrylate (PMMA) bone cement marking a pivotal advancement in spinal surgery. We highlight intraoperative measures like the choice between pre-injecting cement and utilizing cannulated or fenestrated screws, emphasizing the importance of controlling cement viscosity to prevent leakage and embolism. Through two case reports, we demonstrate the practical application of endplate cementation following VBR. CONCLUSION: While the use of cement augmentation poses certain risks, its judicious application-supported by evidence-based guidelines and surgical expertise-can substantially enhance the stability of spinal constructs in osteoporotic patients. This allows a reduction in instrumentation length by enhancing biomechanical stability concerning pullout, bending, and rotational forces. Furthermore, the incidence of endplate sintering following VBF can be significantly reduced. Future research, particularly on antibiotic-loaded PMMA, may further expand its utility and optimize its safety profile.

The Legacy of Harrington's Rod and the Evolution of Long-Segment Constructs in Spine Surgery.

This paper delves into the historical evolution of spinal surgery, focusing on the pivotal role of the Harrington rod in treating spinal deformities. Introduced in 1955, the Harrington rod marked a significant breakthrough in neurosurgery, especially for scoliosis treatment, by offering a novel approach to spinal stabilization. Through a retrospective analysis, this study examines the development and impact of the Harrington rod, highlighting Dr. Paul Harrington's contributions to spinal surgery. His innovative technique revolutionized the management of spinal deformities, laying the groundwork for future advancements in spinal instrumentation. Despite initial skepticism, Harrington's methods gained acceptance, significantly influencing neurosurgical practices and patient outcomes. This study also explores subsequent advancements that built on Harrington's work, including the transition to long-segment spine constructs and the introduction of segmental pedicle screws, which allowed for more precise deformity correction. Reflecting on Harrington's legacy, this paper acknowledges the continuous evolution of spinal surgery, driven by the interplay between clinical challenges and technological innovations. Harrington's pioneering spirit exemplifies the ongoing pursuit of better surgical outcomes, underscoring the importance of innovation in the field of neurosurgery.

Outcome Measures of Open versus Minimally Invasive Surgery for Thoracolumbar Spinal Traumatic Fractures: A Systematic Review and Meta-Analysis.

Objective: To evaluate the efficacy of open and percutaneous pedicle screw fixation in the treatment of thoracolumbar fractures. Methods: Online databases MEDLINE (PubMed), SCOPUS, and Cochrane were searched for English language articles published between January 2001 and December 2023, limited to articles that included the clinical and radiological outcomes of adult patients. The main outcome measures of the study were the Oswestry Disability Index (ODI), the Numeric Rating Scale (NRS) score, and the Cobb angle. Results: A total of 7 studies involving 909 patients were included; 374 (41.1%) procedures were performed with open surgery (OS), while 535 (58.9%) procedures were conducted with minimally invasive surgery (MIS). The mean value of ODI in the MIS group was 8.29% [CI 95% 4.82-11.76], compared to the other group, which was 14.22% (p-value 0.87). Patients receiving a MIS had an average NRS of 1.54 [CI95% 0.98-2.10] whilst OS had 2.31 [CI95% 1.50-3.12] (p-value 0.12). Conclusions: The percutaneous technique is equally safe and effective in resolving the deformity, but the clear advantages are represented by the reduction in blood loss, shorter operative times, a lower incidence of infection, shorter hospitalization, shorter postoperative rehabilitation, and therefore good results in terms of quality of life.

Murine Retina Outer Plexiform Layer Development and Transcriptome Analysis of Pre-Synapses in Photoreceptors.

Photoreceptors in the mammalian retina convert light signals into electrical and molecular signals through phototransduction and transfer the visual inputs to second-order neurons via specialized ribbon synapses. Two kinds of photoreceptors, rods and cones, possess distinct morphology and function. Currently, we have limited knowledge about rod versus (vs.) cone synapse development and the associated genes. The transcription factor neural retina leucine zipper (NRL) determines the rod vs. cone photoreceptor cell fate and is critical for rod differentiation. Nrl knockout mice fail to form rods, generating all cone or S-cone-like (SCL) photoreceptors in the retina, whereas ectopic expression of Nrl using a cone-rod homeobox (Crx) promoter (CrxpNrl) forms all rods. Here, we examined rod and cone pre-synapse development, including axonal elongation, terminal shaping, and synaptic lamination in the outer plexiform layer (OPL) in the presence or absence of Nrl. We show that NRL loss and knockdown result in delayed OPL maturation and plasticity with aberrant dendrites of bipolar neurons. The integrated analyses of the transcriptome in developing rods and SCLs with NRL CUT&RUN and synaptic gene ontology analyses identified G protein subunit beta (Gnb) 1 and p21 (RAC1) activated kinase 5 (Pak5 or Pak7) transcripts were upregulated in developing rods and down-regulated in developing SCLs. Notably, Gnb1 and Gnb5 are rod dominant, and Gnb3 is enriched in cones. NRL binds to the genes of Gnb1, Gnb3, and Gnb5. NRL also regulates pre-synapse ribbon genes, and their expression is altered in rods and SCLs. Our study of histological and gene analyses provides new insights into the morphogenesis of photoreceptor pre-synapse development and regulation of associated genes in the developing retina.

Robotic-assisted surgery for adult spinal deformity. A systematic review.

Purpose: The goal of this systematic review is to offer a detailed summary of the present status of robotic-assisted surgery for adult spinal deformity. Methods: This review is based on articles systematically searched in PubMed, Medline, and Web of Science Core Collection databases on robotic-assisted surgery for adult spinal deformity. Differences in the precision of pedicle screw placement, duration of surgery, and incidence of complications between robotic-assisted surgery and the conventional open surgery were considered. Results: A total of 172 articles were retrieved from the literature search. A total of 168 articles were excluded. Therefore, this systematic review included the remaining four original articles, including accuracy of pedicle screw placement, operative time, radiation exposure, intraoperative and postoperative complications, respectively. The overall level of evidence in the studies was moderate to low. Conclusion: Robotic-assisted surgery for adult spinal deformity demonstrates the potential to enhance the precision of screw placement, possibly reduce intraoperative and postoperative complications, and decrease radiation exposure. However, the impact on operation duration requires further investigation.

Evaluating the Status and Promising Potential of Robotic Spinal Surgery Systems.

The increasing frequency of cervical and lumbar spine disorders, driven by aging and evolving lifestyles, has led to a rise in spinal surgeries using pedicle screws. Robotic spinal surgery systems have emerged as a promising innovation, offering enhanced accuracy in screw placement and improved surgical outcomes. We focused on literature of this field from the past 5 years, and a comprehensive literature search was performed using PubMed and Google Scholar. Robotic spinal surgery systems have significantly impacted spinal procedures by improving pedicle screw placement accuracy and supporting various techniques. These systems facilitate personalized, minimally invasive, and low-radiation interventions, leading to greater precision, reduced patient risk, and decreased radiation exposure. Despite advantages, challenges such as high costs and a steep learning curve remain. Ongoing advancements are expected to further enhance these systems' role in spinal surgery.

Development and validation of deep learning models for identifying the brand of pedicle screws on plain spine radiographs.

Background: In spinal revision surgery, previous pedicle screws (PS) may need to be replaced with new implants. Failure to accurately identify the brand of PS-based instrumentation preoperatively may increase the risk of perioperative complications. This study aimed to develop and validate an optimal deep learning (DL) model to identify the brand of PS-based instrumentation on plain radiographs of spine (PRS) using anteroposterior (AP) and lateral images. Methods: A total of 529 patients who received PS-based instrumentation from seven manufacturers were enrolled in this retrospective study. The postoperative PRS were gathered as ground truths. The training, validation, and testing datasets contained 338, 85, and 106 patients, respectively. YOLOv5 was used to crop out the screws' trajectory, and the EfficientNet-b0 model was used to develop single models (AP, Lateral, Merge, and Concatenated) based on the different PRS images. The ensemble models were different combinations of the single models. Primary outcomes were the models' performance in accuracy, sensitivity, precision, F1-score, kappa value, and area under the curve (AUC). Secondary outcomes were the relative performance of models versus human readers and external validation of the DL models. Results: The Lateral model had the most stable performance among single models. The discriminative performance was improved by the ensemble method. The AP + Lateral ensemble model had the most stable performance, with an accuracy of 0.9434, F1 score of 0.9388, and AUC of 0.9834. The performance of the ensemble models was comparable to that of experienced orthopedic surgeons and superior to that of inexperienced orthopedic surgeons. External validation revealed that the Lat + Concat ensemble model had the best accuracy (0.9412). Conclusion: The DL models demonstrated stable performance in identifying the brand of PS-based instrumentation based on AP and/or lateral images of PRS, which may assist orthopedic spine surgeons in preoperative revision planning in clinical practice.

SafeRPlan: Safe deep reinforcement learning for intraoperative planning of pedicle screw placement.

Spinal fusion surgery requires highly accurate implantation of pedicle screw implants, which must be conducted in critical proximity to vital structures with a limited view of the anatomy. Robotic surgery systems have been proposed to improve placement accuracy. Despite remarkable advances, current robotic systems still lack advanced mechanisms for continuous updating of surgical plans during procedures, which hinders attaining higher levels of robotic autonomy. These systems adhere to conventional rigid registration concepts, relying on the alignment of preoperative planning to the intraoperative anatomy. In this paper, we propose a safe deep reinforcement learning (DRL) planning approach (SafeRPlan) for robotic spine surgery that leverages intraoperative observation for continuous path planning of pedicle screw placement. The main contributions of our method are (1) the capability to ensure safe actions by introducing an uncertainty-aware distance-based safety filter; (2) the ability to compensate for incomplete intraoperative anatomical information, by encoding a-priori knowledge of anatomical structures with neural networks pre-trained on pre-operative images; and (3) the capability to generalize over unseen observation noise thanks to the novel domain randomization techniques. Planning quality was assessed by quantitative comparison with the baseline approaches, gold standard (GS) and qualitative evaluation by expert surgeons. In experiments with human model datasets, our approach was capable of achieving over 5% higher safety rates compared to baseline approaches, even under realistic observation noise. To the best of our knowledge, SafeRPlan is the first safety-aware DRL planning approach specifically designed for robotic spine surgery.

Innovative 3D Navigation Module for Precise Unilateral Pedicle Screw Combined with Contralateral Translaminar Facet Screw Placement in Lumbar Spine Surgery.

OBJECTIVE: The incidence of degenerative diseases of the lumbar spine has increased in recent years. Unilateral pedicle screw combined with contralateral translaminar facet screw fixation offers the advantages of less trauma, better stability, and fewer complications. However, the surgical difficulty and suboptimal pinning accuracy of translaminar facet screw placement in clinical practice limit its use. Therefore, in this study, we designed a novel suspended 3D-printed navigation module to facilitate fast and accurate intraoperative screw placement. The aim of this study is to investigate the digital design, precise implementation, and evaluation methods for placing unilateral pedicle screws in the lumbar spine combined with translaminar facet screw placement using a new suspended 3D navigation module. METHODS: This retrospective study included 46 patients with single-level lumbar lesions who underwent spine surgery at the Affiliated Hospital of Putian University between June 2022 and December 2023. The suspended navigation module was designed digitally. Preoperative screw placement was simulated using 3D printed models, followed by an intraoperative accurate screw placement facilitated by the navigation module and a postoperative evaluation of the accuracy of screw placement. The absolute difference in three-dimensional coordinates of the inlet and outlet points of the preoperative design and the postoperative screw-nail channel served as the precision index. RESULTS: In a study involving 46 patients, surgery was successful with 92 pedicle screws and 46 translaminar facet screws placed without any penetration of the cortex. The difference in coordinates before and after screw insertion was minimal, with entry points varying between 1.21 to 1.36 mm and exit points between 1.97 to 2.46 mm. When screw accuracy met certain thresholds, there was no significant difference between preoperative design and postoperative coordinates, indicating precise replication of the surgical plan. CONCLUSION: The new suspended 3D navigation module enables the precise placement of unilateral pedicle screws in the lumbar spine combined with translaminar pedicle screws for precise surgery.

Transposition Island Pedicle Flap to Repair the Nasal Ala.

Reconstruction of the nasal ala presents surgical challenges, including loss of the nasofacial junction and vasculature compromise, in addition to achieving a cosmetically satisfactory result. The reconstructive surgeon has a variety of closure techniques to employ, but few allow for acceptable cosmesis in a single-stage procedure. The objective of this study is to discuss a novel approach to alar reconstruction using a melolabial-based transposition island pedicle flap, an alternative to traditional interpolated melolabial flaps and inferiorly based interpolated paranasal flap methods. Our reconstruction method utilizes an island pedicle flap harvested from the nasolabial fold and rotated 165˚ medially and superiorly into a surgical defect on the adjacent ala. The pedicle is placed within the alar facial sulcus for a slight trap-dooring effect, recreating the sulcus. The harvest site is closed linearly, resulting in a fusiform scar line to take advantage of the nasolabial fold. Although delicate care is required while dissecting and positioning the flap, it is an otherwise straightforward procedure. The ideal candidate for this technique presents with loss of the alar subunit with an intact alar rim. The only limitation to this style of flap is that the patient has undergone prior procedures involving the ipsilateral nasolabial fold. The transposition island pedicle flap is a well-tolerated alternative to patient cases that require grafting or more involved multi-step reconstructions to efficiently repair nasal alar defects. This technique provides the patient with a presentable cosmetic result using local tissue with minimal post-surgical complications and alar compromise.