Adjacent Anatomical Structures Research Articles

Loss of MMP-27 Predicts Mandibular Bone Invasion in Oral Squamous Cell Carcinoma.

Simple SummaryThe growth of oral squamous cell carcinoma into the mandible poses significant challenges to head and neck surgery. The resulting need for extensive procedures has a decisive influence on subsequent esthetics and function and therefore also on the patient’s quality of life. The molecular mechanism behind this remains obscure to date. Hence, we investigated the influence of MMP-27, Osteoprotegerin and RANKL, three proteins with importance in bone remodeling. The results showed that tumors exhibited less bone-invasive behavior in the presence of MMP-27. This may be an incentive for further studies to elucidate the molecular mechanisms of mandibular bone invasion in OSCC.Invasion of the mandibular bone is frequent in oral squamous cell carcinoma (OSCC), which often results in extensive ablative and reconstructive procedures for the patient. The purpose of this single-center, retrospective study was to identify and evaluate potential biomarkers and risk factors for bone invasion in OSCC. Initially, in silico gene expression analysis was performed for different HNSCC tumor T-stages to find factors associated with invasive (T4a) tumor growth. Afterwards, the protein expression of bone-metabolizing MMP-27, TNFRSF11B (Osteoprotegerin, OPG), and TNFSF11 (RANKL) was investigated via Tissue Microarrays (TMAs) for their impact on mandibular bone invasion. TMAs were assembled from the bone–tumor interface of primary OSCCs of the floor of the mouth and gingiva from 119 patients. Sixty-four carcinomas with patho-histological jaw invasion (pT4a) were compared to 55 carcinomas growing along the mandible without invasion (pT2, pT3). Tissue samples were additionally evaluated for patterns of invasion using the WPOI grading system. Statistical analysis of in silico data revealed decreased MMP-27 mRNA expression to be strongly associated with the pT4a-stage in OSCC, indicating invasive tumor growth with infiltration of adjacent anatomical structures. Our own clinico-pathological data on OSCCs presented a significant decrease of MMP-27 in tumors invading the nearby mandible (pT4a), compared to pT2 and pT3 tumors without bone invasion. Loss of MMP27 evolved as the strongest predictor of mandibular bone invasion in binary logistic regression analysis. To our knowledge, this is the first study investigating the role of MMP-27 expression in OSCC and demonstrating the importance of the loss of MMP-27 in mandibular bone invasion.

Anatomical analysis of different helical plate designs for proximal humeral shaft fracture fixation.

Helical plates are preferably used for proximal humeral shaft fracture fixationand potentially avoid radial nerve irritation. Safety of applying fourdifferent long plate designs (straight, 45°-, 90°-helical and ALPS) with MIPO technique as well as assessment and comparison of their distances to adjacent anatomical structures. MIPO was performed in 16 humancadaveric humeri using either a straight (group1), a 45°-helical (group2), a 90°-helical (group3) plate,or an ALPS (group4). Applying CT angiography, distances between brachial arteries and plates were evaluated. All specimens were dissected and distances to the axillary, radial and musculocutaneous nerve were evaluated. No specimens demonstrated injuries of the anatomical structures at risk after MIPO with all investigated plate designs. Closest overall distance (mean(range); mm) between each plate and the radial nerve was 1(1-3) in group1, 7(2-11) in group2, 14(7-25) in group3 and 6(3-8) in group4. It was significantly bigger in group3 and significantly smaller in group1 compared to all other groups, p < 0.001. Closest overall distance between each plate and the musculocutaneous nerve was 16(8-28) in group1, 11(7-18) in group2, 3(2-4) in group3 and 6(3-8) in group4. It was significantly bigger in group1 and significantly smaller in group3 compared to all other groups, p < 0.001. MIPO with 45°- and 90°-helical plates as well as withALPS is safely feasible and demonstrates significantly bigger distances to the radial nerve compared to straight plates. However, thedistances remain small and attention must be paid to the musculocutaneous nerve and the brachial artery when MIPO is applied using ALPS, 45°- and 90°-helical implants.

Evaluation of the position of the impacted maxillary canine on CBCT

<h3>Objectives</h3> The aim of this study was to evaluate the position of the impacted maxillary canine on CBCT images. <h3>Study Design</h3> CBCT scans of 61 impacted canines in 43 patients were examined. The inclusion criteria were canine impaction, no artifacts that could compromise accurate localization of the impacted tooth, and no pathosis in the maxillae that could compromise evaluation of the tooth. The following canine-impacted related variables were evaluated: impaction side (unilateral, bilateral), impaction location (facial, center, palatal), impaction angulation (vertical, horizontal, oblique), relation to adjacent tooth (central and lateral incisors, first premolar), adjacent anatomical structures (nasal cavity, maxillary sinus, facial or palatal cortices). Patient demographic information was also collected. All variables were assessed by an oral and maxillofacial radiologist. <h3>Results</h3> Among the 43 CBCT scans, the subjects' ages ranged from 9 to 40 years old. Bilateral impacted canines were discovered in 18 subjects unilateral impactions were observed in 25. The impaction location of these canines was observed at the following frequencies: center 47.5%, facial 34.4%, and palatal 18%. Of the 61 impacted canines, the oblique angulation was the most frequent at 63.9%. In total, 78.7% of the impacted canines were in close relationship with the lateral incisor. The impacted teeth were most commonly related to the nasal cavity and maxillary sinus (62.3% and 57.4%, respectively). <h3>Conclusions</h3> CBCT allows the clinician to examine the impacted maxillary canine precisely and guide the surgeon for optimal treatment planning, which may reduce possible post-surgical complications. <b>Statement of Ethical Review</b> Human/Animal subjects were used and this study was approved by an institutional ethics panel

Application of depithelized gracilis adipofascial flap for pelvic floor reconstruction after pelvic exenteration

BackgroundPelvic exenteration is a radical surgery performed in selected patients with locally advanced or recurrent pelvic malignancy. It involves radical en bloc resection of the adjacent anatomical structures affected by the tumor. The authors sought to evaluate the clinical application of a depithelized gracilis adipofascial flap for pelvic floor reconstruction after pelvic exenteration.MethodsA total of 31 patients who underwent pelvic floor reconstruction with a gracilis adipofascial flap after pelvic exenterationat Peking University Third Hospital from 2014 to 2022 were enrolled in the study. The postoperative follow-up durations varied from 4 to 12 months.ResultsThe survival rate of the flap was 96.77% with partial flap necrosis in one case. The total incidence of postoperative complications associated with the flap was 25.81%, with an incidence of 6.45% in the donor site and 19.35% in the recipient site. All complications were early complications, including postoperative infection and flap necrosis. All patients recovered after treatments, including anti-infectives, dressing change, debridement, and local flap repair. Long-term follow-up showed good outcomes without flap-related complications.ConclusionsA depithelized gracilis adipofascial flap can be applied for pelvic floor reconstruction after pelvic exenteration. The flap is an ideal and reliable choice for pelvic floor reconstruction with few complications, an elevated survival rate, sufficient volume, and mild effects on the function of the donor site.

Comparative analysis of imaging investigations in the diagnosis of retroperitoneal tumors

Background: Primary retroperitoneal tumors (PRT) are a group of extremely heterogeneous soft tissue tumors that grow in the retroperitoneal space and have no organic affiliation. Tumors usually become symptomatically late and cause secondary symptoms or become palpable once they have become significantly large. Preoperative diagnosis of PRT is essential for assessing subsequent treatment tactics, planning the approach and volume of surgery, by detecting the structural component, relationships with adjacent anatomical structures and the degree of invasion. Material and methods: Complex prospective and retrospective analysis of clinical, anamnestic and imaging data of 118 patients with primary and nonprimary retroperitoneal tumors, investigated and treated at the Institute of Oncology of the Republic of Moldova during 2015-2020. Results: To determine the primary PRT diagnosis for the clinician, it is primordial to rule out the organic or secondary nature of the tumor. Thus, the patients were examined by: abdominal USG – 118 patients (100%), abdominal and small pelvic contrast-enhanced CT – 118 patients (100%), MRI – 3 patients (2.5%), videoesogastroduodenoscopy – 32 patients (27.1%), videocolonoscopy – 31 patients (26.3%), irigography – 4 patients (3.4%), urography – 29 patients (24.6%). Conclusions: Contrast-enhanced CT provides more accurate data than USG. The image obtained at the USG examination is flat, therefore the dimensional measurements of the tumor are not always performed on the longest tumor axis, especially in the case of polylobulated or giant tumors, while the tomographic examination techniques allow the three-dimensional reconstruction of the tumor with more accurate assessment of the tumor size.

Cone beam computed tomographic evaluation of infraorbital canal protrusion into the maxillary sinus and its importance for endoscopic surgery

ObjectiveThe aim of this retrospective study is to investigate the prevalence of Infraorbital Canal Protrusion (ICP) degree into the maxillary sinus and its relationship with variations in adjacent structures on Cone Beam Computed Tomography (CBCT) images. Methods350 CBCT images (700 Infraorbital Canal [IC]) were evaluated retrospectively. ICP was divided into 3 subtypes according to the protrusion degree. The correlation between IC types and variations in adjacent anatomical structures (Haller cell, middle nasal concha pneumatization, maxillary sinus mucosal thickening and septa) was evaluated. The distance between Infraorbital Canal and Cnine Root (IC-CR) was also measured. For type 3, measurements were performed on IC as the length of the bony septum from the IC to the Mxillary Sinus Wall (IC-MSW), the distance from the inferior orbital rim, where the IC begins to protrude into the maxillary sinus (IOR-ICP), the vertical distance from the IC to the Maxillary Sinus Roof (IC-MSR) and Floor (IC-MSF). ResultsThe prevalence of type 1, 2 and 3 was 62.9%, 29.1%, and 8% respectively. IC-CR was 10.2, 10.7 and 11.4 mm in type 1, 2 and 3, respectively. IC-MSW, IOR-ICP, IC-MSR and floor IC-MSF was 3.8, 10.9, 7.4 and 27.7 mm, respectively. On the right and left side, statistically significant correlation was found between IC types and the presence of the Haller cell and sinus septa. But there was no significant correlation between IC types and middle concha pneumatization. ConclusionAccurate diagnosis of ICP is very important in preventing infraorbital nerve damage in surgical procedures to be performed in the maxillary region. The results of this study could be a guide for surgical planning in this region. Level of evidenceRetrospective study.

Is Wrist Arthroscopy Safer with the Nanoscope?

Background Nanoscope, given its smaller size, may be safer when establishing dorsal wrist arthroscopy portals compared with the traditional 2.7 mm arthroscope. Case Description Ten fresh frozen cadaver specimens were utilized. Dorsal radiocarpal portals were established with the Nanoscope and calipers were used to measure the distance between the portals and the surrounding anatomical structures. The only structure that was pierced during portal placement was the dorsal sensory branch of the ulnar nerve (DSUN) in one specimen when establishing the 6U portal. Our study did not note any tendon injuries. Literature Review Traditional wrist arthroscopy may be performed with a 2.7 mm arthroscope. With its larger outer sheath cannula, this may place adjacent anatomical structures at risk of injury. Clinical Relevance During wrist arthroscopy, the Nanoscope may be safer when creating portals to underlying structures. Level of Evidence This is a Level IV study.

An anatomical study of the meniscal roots of the knee: landmarks for its surgical reconstruction and implications for knee surgeons.

The aim of this anatomical study was to describe the anatomy of the meniscal roots and their relationships with respect to the main adjacent structures in order to improve their surgical reconstruction. Fourteen knees were included. The mean age of the donors was 92years (range 89-96). We studied the general characteristics of the anterior and posterior roots of the medial meniscus and lateral meniscus by measuring their widths at their base and area. We investigated the relations between anterior and posterior roots of the medial and lateral menisci with respect to the anterior and posterior cruciate ligaments (ACL and PCL). The mean width of the anterior root of the lateral meniscus was 10.5 ± 1.4mm. The mean width of the anterior root of the medial meniscus was 10 ± 1.5mm. The mean width of the posterior root of lateral meniscus was 11.4 ± 1.4mm. The mean width of the posterior root of medial meniscus was 10.5 ± 1.0mm. The mean distance between the anterior cruciate ligament and the anterior root of lateral meniscus was 9.8 ± 2.9mm, for the medial meniscus it was 15.9 ± 3.4mm. The mean distance between the posterior cruciate ligament and the posterior root of the lateral meniscus was 11.5 ± 2.7mm, for the medial meniscus, it was 11 ± 2.6mm. The anterior and posterior meniscal roots have precise landmarks, and this article contributes to define the location of the meniscal roots with respect to their adjacent anatomical structures: ACL, PCL and intercondylar tubercle. Having precise measures of the distances between the meniscus roots and these structures allows knee surgeons to perform ACL reconstruction, meniscal root repair and meniscal allograft transplantation.

Características anatómicas del nervio mediano en el codo y antebrazo proximal

IntroductionKnowledge of anatomy of the median nerve in its course through the elbow allows understanding the origin of several pathologies; in addition, identifying the distribution and anatomical variants of the nerve branches is useful for defining surgical approaches for this nerve. Materials and methodsDissection of cadaveric specimens, convenience sample, with prior approval of the ethics committee and following a dissection protocol identifying the median nerve and its ramifications in the elbow and its relationship with vascular and myotendinous structures. ResultsTwenty elbows with an average age of 60.8 years were dissected, exploring the median nerve, its ramifications and adjacent anatomical structures in the antecubital fossa. No Struthers ligament was found, the distance to the pronator teres (PT) arcade from the interepichondyle line was 51.3mm and 74.1mm to the flexor digitorum superficialis (FDS) arch. The most frequent pattern was a trunk for PT, a proximal transverse branch with divisions for FDS, flexor carpi radialis (FCR) and palmaris longus (PL). The innervation of the FCR originated mostly from the trunk of the PT. DiscussionGreat variability of origin and distribution of the branches originated from the median nerve in the elbow was observed, the distances and morphological characteristics in the known compression sites were quantified. The FCR branch is put at risk in the exploration of the tendon arches of the PT and the FDS.

Odontogenic fibromyxoma: A case report in myasthenia gravis patient and review of the literature.

Introduction and importanceOdontogenic fibromyxoma is generally slow-growing, benign, asymptomatic, present with painless swelling in the jaw. Pain is mostly seen in the case of infection, adjacent anatomical structures or neural involvement. When the English-language literature is searched, only 62 cases are found about odontogenic fibromxoma which means it is really rare pathology.Case presentationWe describe a case of odontogenic fibromyxoma in a 29-year-old female with Myasthenia Gravis (MG) who referred to oral and maxillofacial surgeon with increased swelling in the anterior region of the mandible.Clinical discussionClinically, there was swelling in the mouth that caused bone expansion. On the radiological examination, a well-circumscribed, radiolucent area causing displacement of the tooth roots was observed. After clinical and radiological examinations, the operation was done under local anesthesia. The excised lesion was sent for histopathological investigation and the patient was followed up clinically and radiologically for 3 years.ConclusionThe clinical and radiological properties, differential diagnosis, treatment options and prognosis of odontogenic fibromyxomas are also discussed after the case presentation along with literature review.

Anatomical analysis of different helical plate designs for proximal humeral shaft fracture fixation

Abstract Objective Helical plates are preferably used for proximal humeral shaft fracture fixation with metaphyseal extension into the humeral head and potentially avoid radial nerve irritation as compared to straight plates. The aims of this study were: (1) to investigate the safety of applying different long plate designs (straight, 45°-, 90°-helical and ALPS) in MIPO-technique to the humerus and (2) to assess and compare their distances to adjacent anatomical structures at risk. Methods MIPO was performed in 16 human cadaveric humeri using either a straight plate (group1), a 45°-helical (group2), a 90°-helical (group3) or an ALPS (group4). Using CT-angiography, distances between brachial arteries and plates were evaluated. Following, all specimens were dissected, and distances to the axillary, radial and musculocutaneous nerve were evaluated. Results None of the specimens demonstrated injuries of the anatomical structures at risk after MIPO with all investigated plate designs. Closest overall distance (mm(range)) between each plate and the radial nerve was 1(1–3) in group1, 7(2–11) in group2, 14(7–25) in group3 and 6(3–8) in group4. It was significantly longer in group3 and significantly shorter in group1 as compared to all other groups, p&amp;lt;0.001. Closest overall distance (mm(range)) between each plate and the musculocutaneous nerve was 16(8–28) in group1, 11(7–18) in group2, 3(2–4) in group3 and 6(3–8) in group4. It was significantly longer in group1 and significantly shorter in group3 as compared to all other groups, p&amp;lt;0.001. Closest overall distance (mm(range)) between each plate and the brachial artery was 21(18–23) in group1, 7(6–7) in group2, 4(3–5) in group3 and 7(6–7) in group4. It was significantly longer in group1 and significantly shorter in group3 as compared to all other groups, p&amp;lt;0.021. Conclusion MIPO with 45°- and 90°-helical plates as well as ALPS is safely feasible and showed a significant greater distance to the radial nerve compared to straight plates. However, distances remain low, and attention must be paid to the musculocutaneous nerve and the brachial artery when MIPO is used with ALPS, 45°- and 90°-helical implants. Moreover, the anterior part of the deltoid insertion will be detached when using 90°-helical and ALPS implants in MIPO-technique.

Anatomical analysis of different helical plate designs for distal femoral fracture fixation

Abstract Objective Helical plates potentially avoid the medial neurovascular structures of the thigh. Recently, two plate designs (90°- and 180°-helix) proved similar biomechanically behavior compared to straight plates. The aims of this study were: (1) feasibility of applying 90°- and 180°-helical plates in MIPO-technique to the femur, (2) Assess the distances to adjacent anatomical structures which are at risk, (3) Compare these distances with medial straight plates, and (4) Correlate measurements performed during anatomical dissection with CT-angiography. Methods MIPO was performed in ten cadaveric femoral pairs using either a 90°-helical 14-hole-LCP (group1) or a 180°-helical 15-hole-LCP-DF (group2). Using CT-angiography, distances between femoral arteries and plates as well as distances between plates and perforators were evaluated. Following, specimens were dissected, and distances determined again. All plates were removed, and all measurements were repeated with straight medial plates (group3). Results Closest overall distances between plates and femoral arteries were 15 mm(11–19 mm) in group1, 22 mm(15–24 mm) in group2 and 6 mm(1–8 mm) in group3 with a significant difference between group1 and group3(p&amp;lt;0.001). Distances to the nearest perforators were 24 mm(15–32 mm) in group1 and 2 mm(1–4 mm) in group2. Measurement techniques (visual after surgery and CT-angiography) showed a strong correlation of 0.972(p&amp;lt;0.01). Conclusion MIPO with 90°- and 180°-helical plates is feasible and safe. Attention must be paid to the medial neurovascular structures with 90°-helical implants and to the proximal perforators with 180°-helical implants. Helical implants can avoid medial neurovascular structures compared to straight plates although care must be taken during their distally insertion. Measurements during anatomical dissection correlate with CT-angiography.

Carbon-fiber-reinforced polyetheretherketone orthopedic implants in musculoskeletal and spinal tumors: imaging and clinical features.

Carbon-fiber-reinforced polyetheretherketone (CFR-PEEK) orthopedic implants are gaining popularity in oncologic applications as they offer many potential advantages over traditional metallic implants. From an imaging perspective, this instrumentation allows for improved evaluation of adjacent anatomic structures during radiography, computed tomography (CT), and magnetic resonance imaging (MRI). This results in improved postoperative surveillance imaging quality as well as easier visualization of anatomy for potential image-guided percutaneous interventions (e.g., pain palliation injections, or ablative procedures for local disease control). CFR-PEEK devices are also advantageous in radiation oncology treatment due to their decreased imaging artifact during treatment planning imaging and decreased dose perturbation during radiotherapy delivery. As manufacturing processes for CFR-PEEK materials continue to evolve and improve, potential orthopedic applications in the spine and appendicular skeleton increase. An understanding of the unique properties of CFR-PEEK devices and their impact on imaging is valuable to radiologists delivering care to orthopedic oncology patients in both the diagnostic and interventional settings. This multidisciplinary review aims to provide a comprehensive insight into the radiologic, surgical, and radiation oncology impact of these innovative devices.

Is the Use of Intraoperative 3D Navigation for Thoracolumbar Spine Surgery a Risk Factor for Post-Operative Infection?

Pedicle screw fixation is a technique used to provide rigid fixation in thoracolumbar spine surgery. Safe intraosseous placement of pedicle screws is necessary to provide optimal fixation as well as to avoid damage to adjacent anatomic structures. Despite the wide variety of techniques available, none thus far has been able to fully eliminate the risk of malpositioned screws. Intraoperative 3-dimensional navigation (I3DN) was developed to improve accuracy in the placement of pedicle screws. To our knowledge, no previous studies have investigated whether infection rates are higher with I3DN. A single-institution, retrospective study of patients age > 18 undergoing thoracolumbar fusion and instrumentation was carried out and use of I3DN was recorded. The I3DN group had a significantly greater rate of return to the operating room for culture-positive incision and drainage (17 (4.1%) vs. 1 (0.6%), p = 0.025). In multivariate analysis, the use of I3DM did not reach significance with an OR of 6.49 (0.84–50.02, p = 0.073). Post-operative infections are multifactorial and potential infection risks associated with I3DN need to be weighed against the safety benefits of improved accuracy of pedicle screw positioning.

Postcoital Ejaculatory Groin Pain Response to Blood Flow Restriction Training

The most common sign of male sexual dysfunction is ejaculatory pain following coitus. It is brought on by a number of factors including postsurgical treatments, tight or weak muscles, or any injury to the testes or adjacent anatomical structures. A 21-year-old male gym trainer experienced groin pain bilaterally during postcoital ejaculation for 2 weeks. The Numeric Pain Rating Scale (NPRS) recorded 7 out of 10 for the level of pain, for which the patient was advised to perform Kegel exercises, traditional physiotherapeutic exercises, and blood flow restriction training (BFRT). Eventually, posttreatment, the pain intensity decreased to 3 on NPRS. This unique case of postcoitus ejaculatory adductor tendon pain highlights the beneficial effects of both Kegel exercises and conventional exercise routines in addition to BFRT. This case is a novel finding and is unique, so it cannot be examined on a large scale.

Importancia del uso de la imagenología pre e intraoperatoria como herramienta para la planificación de remoción de cuerpo extraño en piso de boca. Presentación de un Caso

Introduction: Body piercings consist of small holes made with a needle in different parts of the skin or body to introduce a jewel or decorative element. In the oral cavity, most piercings are placed in the tongue. However, some complications may occur, and surgical techniques must be used for their removal. These complications present a certain degree of difficulty due to their position and may challenge the ability of the clinician to access the specific anatomical location. The different imaging techniques, from simple radiography to intraoperative techniques such as image intensifiers, have become an extremely useful tool for locating an object in the three dimensions of space, allowing safe location and extraction. Objective: The aim of this study is to report the case of a complication of a body piercing in the oral cavity and how the use of imaging was decisive for surgical planning and for the quick and effective resolution of the case. Material and Methods: A 14-year-old female patient came looking for treatment. Her mother reported the onset of the condition after the insertion of a needle-like metallic object while performing an artistic perforation in the lingual region. Since the girl was unable to extract the object, she sought medical advice at the Carlos Arvelo Military Hospital in Caracas, Venezuela. Subsequently, an imaging study was performed by means of a Computed Tomography to locate the metallic object. It was observed that the foreign body had migrated to the floor of the mouth/sublingual region, requiring the area to be surgically approached. It was also decided to use an intraoperative image intensifier. The removal of the object was performed satisfactorily. Conclusion: The extraction of foreign bodies placed in the lingual and sublingual region represents a challenge for the clinician due to the number of important anatomical structures that pass through that area. This makes clinicians plan their surgical removal using pre- and intraoperative imaging, to find a less traumatic location, reduce surgical time as well as the risk of damaging adjacent anatomical structures.

Anatomical analysis of different helical plate designs for distal femoral fracture fixation

PurposeHelical plates potentially avoid the medial neurovascular structures of the thigh. Two implant designs for additional medial 90° helical plate in double plate constructs for geriatric patients and 180° helical plate for single plating in young patients are potential alternatives to widely used standard straight plates. Aims: (1) assess the distances to adjacent anatomical structures being at risk when applying medial 90° and 180° helical plates with MIPO technique to the femur, (2) compare these distances with medial straight plates, and (3) correlate measurements performed during surgical dissection with CT angiography. MethodsMIPO was performed in ten human cadaveric femoral pairs using either a 90° helical 14-hole LCP (Group 1) or a 180° helical 15-hole LCP-DF (Group 2). Using CT angiography, distances between femoral arteries and plates as well as distances between plates and perforating vessels were evaluated. Following, specimens were dissected and distances determined again. All plates were removed and measurements were repeated with straight medial plates (Group 3). ResultsOverall closest distances between plates and femoral arteries were 14.5 mm (11–19 mm) in Group 1, 21.6 mm (15–24 mm) in Group 2 and 6.5 mm (5–8 mm) in Group 3, with significant differences between Group 3 and both other groups (p < 0.001). Distances to the nearest perforating vessels were 22.4 mm (15–30 mm) in Group 1 and 1.2 mm (1–2 mm) in Group 2. Measurement techniques (visual after surgical disection and CT angiography) demonstrated a strong correlation (p < 0.010). ConclusionsInserting 90° and 180° helical plates with MIPO technique is safe, however, attention must be paid to the medial neurovascular structures with 90° helical plates and to the proximal perforating vessels with 180° helical plates. Helical plates can avoid irritation of medial neurovascular structures – compared with straight plates – although care must be taken during their distal insertion. Measurements during surgical dissection correlate with CT angiography.

Recurrent Glomus Jugulare Tumor Invading the Cerebellum on 68Ga-DOTATATE PET/CT.

Glomus tumors are rare, slow-growing extra-adrenal paragangliomas of the head and neck. Treatment and prevention of neurological deficits become more difficult as these tumors aggressively grow in size and infiltrate adjacent anatomical structures. Because glomus tumors are paragangliomas of neuroendocrine origin, 68Ga-DOTATATE PET/CT can be used as imaging method in the diagnosis and follow-up. In this case, we presented a recurrent glomus jugulare tumor that invaded to the cerebellum on 68Ga-DOTATATE PET/CT imaging.

Effect of a digital guide on the positional accuracy of intermaxillary fixation screw implantation in orthognathic surgery

Intermaxillary fixation screw (IMFS) implantation is a common procedure in orthognathic surgery (OGS) performed to the temporary maxillary-mandibular fixation and stable bite relationships. The study aims to assess the accuracy of IMFS implantation with a digital guide to reduce the occurrence of root damage. This prospective study involved 40 patients undergoing OGS at the Affiliated Hospital of Qingdao University from August 2017 to May 2021. The patients were randomly divided into two groups according to whether the IMFS implantation was with or without digital guide (20 patients in the experimental group and 20 controls). The digital guides used in the experimental group were designed according to a virtual implantation plan and printed using stereolithography. In the control group, IMFSs were directly implanted by a surgeon based on clinical experience. Postoperatively, cone-beam computed tomography was performed to compare root proximity of IMFSs between the two groups and verify the accuracy of IMFS placement. In the experimental group, there was no case of root damage, the incidence of the periodontal ligament (PDL) injured was 22.1%, and 77.9% IMFSs were placed without contacting adjacent anatomic structures. In the control group, the incidence of root damage had been up to 20.8%, 31.7% IMFSs injured the PDL, and only 47.5% IMFSs were placed between the roots (P<0.001). IMFSs can be placed more accurately with surgical guides, reducing the incidence of root and PDL damages.

Morphology of the trigeminal ganglion: anatomical structures related to trigeminal radiofrequency rhizotomy.

Trigeminal neuralgia is the most common example of craniofacial neuralgia. Its etiology is unknown and is characterized by severe episodes of paroxysmal pain. The trigeminal ganglion and its adjacent anatomical structures have a complex anatomy. The foramen ovale is of great importance during surgical procedures such as percutaneous trigeminal rhizotomy for trigeminal neuralgia. We aimed to identify the anatomical structures associated with the trigeminal ganglion and radiofrequency rhizotomy on cadavers and investigate their relationship with the electrodes used during rhizotomy to determine the contribution of the electrode diameter and length to the effectiveness of the lesion formation on the ganglion. Five fresh-frozen cadaver heads injected with red silicone/latex were used. A percutaneous puncture was made by inserting of a cannula through the foramen ovale to create a pathway for electrodes. The relationships between the electrodes, Meckel's cave, trigeminal ganglion, and neurovascular structures were observed and morphometric measurements were obtained using a digital caliper. Trigeminal ganglion, therefore the electrode in its final position, shows proximity with important anatomical structures. The electrode was inserted posteriorly into the foramen ovale in all of the specimens and was located on the retrogasserian fibers. This study revealed that the electrodes targeting the ganglion and passing through the foramen ovale may cause a radiofrequency lesion due to the contact effect of the dura itself pressing on the electrode. Pushing the cannula beyond the petroclival angle may result in puncturing of the dura propria and moving further away from the target area. The success of radiofrequency rhizotomy is directly related to the area affected by the lesion. Understanding the mechanism of action underlying this procedure will ensure the effectiveness, success, and sustainability of the treatment.