Lateral Pterygoid Plate Research Articles

Anatomical variations of the lateral pterygoid plate and their implications for temporomandibular disorders: A CBCT study

ObjectiveTMD is a multifaceted condition with various contributing factors, but the actual impact of the lateral pterygoid plate on the development of TMD remains uncertain. This research aims to investigate the relationship between anatomical variations of the lateral pterygoid plate (LPP), including its angle and proximity to the condyle, and the prevalence of temporomandibular disorders (TMD), to improve diagnostic accuracy and therapeutic approaches for TMD. Materials & MethodsA retrospective analysis was conducted on 189 Cone Beam Computed Tomography (CBCT) images of individuals aged 18 to 45. Inclusion criteria were based on definitive diagnoses of degenerative joint disease, excluding individuals with orthodontic treatments, injuries, or craniofacial disorders.Participants were divided into TMD and control groups using standardized DC/TMD protocols for assessment. A radiologist, blinded to the patient's clinical status, then analyzed the CBCT images. LPP dimensions, angles, and condyle distances were measured using OnDemand 3D Imaging Software. ResultsThe study found a statistically significant higher average LPP length in females compared to males (right LPP p < 0,001, left LPP p = 0,004), with no significant differences in LPP-condyle distances and angles between genders. Comparing the TMD and control groups revealed a positive correlation between lateral plate angles and TMJ disorders (p = 0,044), suggesting a potential biomechanical linkage. ConclusionConclusively, the study challenges the assumption that LPP anatomical variations significantly impact TMD while underscoring a potential link between LPP angle and TMD. The novel insight into the potential role of the LPP angle in TMD provides a new direction for research and clinical practice, emphasizing the importance of considering subtle anatomical differences in the management of TMD.

Pterygoideus proprius muscle: stuck between the greater wing and lateral pterygoid plate.

The muscles of mastication derive from a common embryological source, and the presence of accessory muscles in the infratemporal fossa (ITF) is uncommon. Here, we present findings from postmortem dissection of the ITF revealing a unilaterally present muscle extending from the greater wing of the sphenoid to blend inferiorly with the medial and lateral pterygoid muscles before attaching to the lateral pterygoid plate. This muscle is most consistent with the pterygoideus proprius muscle initially described in 1858. Though the exact embryological origin and function of this muscle remain speculative, these topics are nonetheless worth investigating as it may provide insight regarding the ontogeny of muscles descending from the first pharyngeal arch. Additionally, presence of the pterygoideus proprius muscle may have clinical implications and impact surrounding structures such as the mandibular division of the trigeminal nerve, maxillary artery, pterygoid venous plexus, masticatory muscles, and temporomandibular joint (TMJ).

Numerical study of the impact of osteotomies and distractor location in surgically assisted rapid palatal expansion for transverse maxillary deficiency

IntroductionThis paper employs finite element analysis to assess the biomechanical behavior of surgically assisted rapid palatal expansion (SARPE) with a bone-borne transpalatal distractor (TPD) by varying surgical parameters. Material and methodsNine models were constructed to scrutinize the effects of pterygomaxillary disjunction (PMD), lateral osteotomy positioning, and TPD placement on displacement profiles and Von Mises stresses. These models encompassed variations such as no, unilateral or bilateral PMD, asymmetrical lateral osteotomy, and five TPD locations. ResultsPerforming a PMD reduces posterior resistance to transverse expansion, resulting in 10–20 % stress reduction around the maxillofacial complex. No significant changes in horizontal tipping were observed post-PMD. The asymmetric lateral osteotomy model exhibited larger displacements on the side with a more superiorly positioned osteotomy. Reduced stresses were observed at the maxillary body and medial pterygoid plate (superiorly), while increased stresses were observed at the medial (inferiorly) and lateral pterygoid plates. More posterior TPD placement facilitated more parallel expansion thus less horizontal tipping, albeit with increased vertical tipping. DiscussionSARPE procedures (distractor and osteotomy positions) can be tailored based on desired outcomes. PMD reduces stress within the maxillofacial complex but doesn't significantly affect tipping. Higher lateral osteotomies lead to increased displacements, more posterior distractors to more parallel expansion.

Suture-like pattern formation in the pterygospinous bridge of the human sphenoid bone.

The paper presents an anatomical study involving rare variations in the pterygospinous bridges found in Mongolian skulls. These structures extend between the lateral pterygoid plate and the sphenoid spine. Particularly interesting is the division of these bridges into two distinct parts of the similar length. The junctions within these structures resemble morphological patterns characteristic for the plain and zigzag sutures, which articulate the cranial bones.

The sphenopterygoid canal and pterygoid foramen.

In human anatomy, there are well-known the foramina of the greater sphenoidal wing, the foramen rotundum, the foramen ovale, the foramen spinosum, as well as the inconstant sphenoidal emissary foramen of Vesalius and the foramen of Arnold. Different canals are found in several species of rodents, such as the alisphenoid and sphenopterygoid (SPC) canals. It was re-explored an archived computed tomography angiogram of a 60 y.o. female case. Bilateral superior recesses of the pterygoid fossae (SRPF) and a right SPC were found. The SRPF on each side penetrated the non-lamellar pterygoid root and superiorly reached the sphenoidal sinus wall. Upper fibres of medial pterygoid muscles were inserted into each SRPF. An unexpected SPC was found on the right side. It opened superiorly on the lateral side of the foramen rotundum and inferiorly at a pterygoid foramen in the superior end of the posterior margin of the lateral pterygoid plate. A sphenoidal emissary vein traversed that SPC to drain into the pterygoid plexus. The SRPF and SPC could also be found in humans. As the sphenoidal emissary veins are surgically relevant, they should not be further regarded as exclusively crossing the foramen of Vesalius but also the SPC.

Musculus pterygoideus proprius: A meta-analysis.

The pterygoideus proprius muscle can be found incidentally in the infratemporal fossa, where it is spatially associated with the muscles of mastication, the maxillary artery, and the trigeminal nerve and its branches. Anatomists have described the muscle in various ways over the past 160 years, chiefly as a musculotendinous structure that originates from the infratemporal crest of the sphenoid bone and inserts into the lateral pterygoid plate and the lateral pterygoid muscle. It is present in non-human primates, albeit rarely, with similar anatomical findings. Embryologically, the pterygoideus proprius is thought to have developed from the first pharyngeal arch mesenchyme along with other muscles of mastication. Its close association with the maxillary artery and trigeminal nerve suggests possible clinical significance in trigeminal neuralgia and temporomandibular joint disorders. The literature was reviewed systematically to detail the historical background of research on the pterygoideus proprius muscle and explain its morphology, prevalence, embryology, and potential clinical significance. Despite its rarity, we propose that it is important to recognize its presence when the infratemporal fossa is approached.

A morphological study on the sphenoid bone ligaments’ ossification pattern

PurposeThe sphenoid bone (SB) extracranial ligaments (ECRLs) are the pterygoalar and pterygospinous ligaments (PTAL and PTSL) that are located at the SB lateral pterygoid plate, and inferior to the foramen ovale (FO). Their ossification may affect the mandibular nerve’s distribution. The intracranial ligaments’ (ICRLs) ossification (the caroticoclinoid ligament—CCLL, the anterior and posterior interclinoid ligaments—AICLL and PICLL) may impede the approaches to the sella.This study highlights the incidence of the ossified ECRLs and ICRLs location, their type (partial, or complete), considering laterality, gender, age, and ligaments’ simultaneous presence.MethodsThe sample consisted of 156 Greek adult dried skulls of both genders and variable age.ResultsOssified ligaments were identified in 57.05%, predominantly extracranially (42.31%, P = 0.003). ECRLs were predominantly identified unilaterally (30.13%, P < 0.001). The majority of the ossified ICRLs were predominantly identified in male skulls (31.1%, P = 0.048) and the majority of the ECRLs (52.8%, P = 0.028) were predominantly identified at the age of 60 years and above. The PTAL was the most ossified (32.69%), followed by the CCLL (24.36%), the PTSL (16.03%), the PICLL (6.41%), and the AICLL (4.49%).ConclusionsDetailed knowledge of the SB morphology and ligaments’ ossification extent is essential to improve the technique of the FO percutaneous approach, and sellar approaches, to minimize complications.

Refining the Anatomy of Percutaneous Trigeminal Rhizotomy: A Cadaveric, Radiological, and Surgical Study.

Percutaneous trigeminal rhizotomy (PTR) is a widely used procedure for trigeminal neuralgia. However, comprehensive analyses that combine anatomic, radiological, and surgical considerations are rare. To present high-quality anatomic dissections and radiological studies that highlight the technical nuances of this procedure. Six silicon-injected postmortem heads underwent PTR. The surgical corridors were dissected, and the neurovascular relationships were studied. In addition, 20 dried human skulls and 50 computed tomography angiography and MRI scans were collected to study the anatomic relationships for a customized puncture corridor. The PTR corridor was divided into 3 segments: the buccal segment (length, 34.76 ± 7.20 mm), the inferior temporal fossa segment (length, 42.06 ± 6.92 mm), and the Meckel cave segment (length, 24.75 ± 3.34 mm). The puncture sagittal (α) and axial (β) angles measured in this study were 38.32° ± 4.62° and 19.13° ± 2.82°, respectively. The precondylar reference line coincided with the foramen ovale in 75% of the computed tomography angiography scans, and the postcondylar line coincided with the carotid canal in 70% of the computed tomography angiography scans; these lines serve as the intraoperative landmarks for PTR. The ovale-carotid-pterygoid triangle, delineated by drawing a line from the foramen ovale to the carotid canal and the lateral pterygoid plate, is a distinguished landmark to use for avoiding neurovascular injury during fluoroscopy. Knowledge of the anatomic and radiological features of PTR is essential for a successful surgery, and a customized technical flow is a safe and effective way to access the foramen ovale.

Effects of different distractor positions on the formation of expansion, stress and displacement patterns in surgically assisted rapid maxillary expansion without pterygomaxillary disjunction: a finite element analysis study

Skeletal orthopedic expansion of maxilla is accepted as a reliable method for the treatment of transverse maxillar deficiency in growing patients. The aim of the study was to evaluate the effects of different palatal distractor positions on the expansion, stress and displacement patterns of the structures of craniofacial complex in surgical assisted rapid maxillary expansion without pterygomaxillary disjunction (PTMD) with the help of finite element analysis(FEA). Four facial skeleton models with different distractor positions (first premolar, second premolar, first molar, second molar regions) were created. In all finite element models median and lateral osteotomies were performed, without PTMD. Stress distribution was evaluated after 5 mm activation of the transpalatal distraction in all models using the nonlinear solution method in FEA. Unilateral displacement(mm) and stress distribution(MPa) were measured in three directions (x, y, and z axes) of craniofacial and maxillofacial structures in the symmetrical finite element models. In all models, the unilateral transverse displacements of the anterior teeth were greater than those of the posterior teeth, and the greatest displacement was at the central incisor level. The greatest displacement values at the central incisor level, at the anterior nasal spine(ANS) and at the posterior nasal spine(PNS) levels was measured in Model-IV, III, II and I, respectively. Mean elemental stress(von Mises stress) in the medial pterygoid plate, screw and lateral pterygoid plate regions from highest to lowest was measured in Model-IV, III, II and I, respectively. The maxilla performed outward rotation and tipping movement in all models during the expansion period. Among the distractor positions, the second molar region was found to be the most advantageous one in terms of expansion pattern. Considering the patient’s anatomy and clinical conditions, placing the palatal distractor as posteriorly as possible will result in more effective maxillary expansion.

Radiological anatomy of foramen rotundum and its surgical implications

IntroductionThe use of endoscopic sinus surgery in the field of otorhinolaryngology is due to many reasons such as better visualization, the complex anatomy of the skull base and the relations between vital vascular and nervous elements, the crucial preoperative knowledge about the detailed anatomy of the area, and the computed tomography that is a useful tool for them to plan the safest route of surgery. The foramen rotundum (FR) is the inherent bony structure in the skull base located in the greater wing of the sphenoid bone on the floor of the middle cranial fossa, located adjacent to the nasopharynx, and often invaded by nasopharyngeal cancer and other malignant brain tumors. The This study aims to give a detailed description of anatomical variations of FR, as well as its relationships with the surrounding vital structures, to instruct a preoperative planning for endoscopic surgery.MethodsThe distances between the foramen rotundum and fixed anatomical landmarks like the nasal floor and pterygoid process were measured in 200 foramen rotunda of 100 patients older than 18 years old and without known skull base pathology. The patients included in this study were demonstrated and evaluated separately using a multislice computed tomography (CT) technique with DICOM viewing software (Osirix or Horos).ResultsThe average horizontal distance between the FR and vidian canal (VC) on each side, vertical distance between FR and VC on each side, direct distance between the FR and VC on each side, FR diameter, rotundum angles, FRs and nasal floor angles, and FR and optic nerve distances calculated has no significant difference. The P values were 0.471, 0.521, 0.072, 0.283, 0.952, 0.661, and 0.663, respectively. The gender comparison in the present study showed no significant distances on both the right and left sides. The P values 0.765, 0.879, 0.621, 0.297, 0.992, and 0.227 were direct, horizontal, and direct distances, respectively.ConclusionsThis study provides more light on the anatomy of the foramen rotundum with the other anatomical/surgical key structures used in endonasal surgeries such as the lateral pterygoid plate and vidian canal.

Pattern of pterygomaxillary disarticulation associated with Le Fort I maxillary osteotomy

Pterygomaxillary disarticulation (PMD) contributes to surgical complications of Le Fort 1 osteotomy and is associated with undesirable fractures of the pterygoid plates. The aim of this paper was to investigate the patterns of PMD in Le Fort I osteotomies using Rowe's disimpaction forceps, and to evaluate correlations with age and anatomical measurements. Cone-beam computed tomography (CBCT) scans of 70 consecutive orthognathic patients were retrospectively evaluated to study four patterns of PMD: Type 1 - PMD at, or anterior to, the pterygomaxillary junction (PMJ); Type 2 - PMD posterior to the PMJ; Type 3 - PMJ separation with comminuted fracture of the pterygoid plates; Type 4 - disarticulation of the maxilla involving the pterygoid plates above the level of the osteotomy line. The preoperative anteroposterior and mediolateral thicknesses of the PMJ and the length of the medial and lateral pterygoid plates were assessed. Satisfactory PMD was achieved in all cases and no severe complications were reported, including vascular, dental, mucosal, or neural damage. The most common PMD was Type 1 (54.3%), followed by Type 2 (40%). Comminuted fracture of the pterygoid plates was limited to 5.7% of cases, and no Type 4 was detected. A weak correlation was detected between PMJ thickness and PMD pattern (p = 0.04). No statistically significant correlation was detected between patients’ age and type of PMD. PMD of Le Fort I maxillary osteotomy using a Smith spreader and Rowe's disimpaction forceps proved safe, with minimal damage to the pterygoid plates.

Percutaneous radiofrequency ablation of peripheral maxillary nerve: Description of new methodology.

Sir, Maxillary nerve is the second most affected branch in trigeminal neuralgia. It is treated with medical drugs like carbamazepine and baclofen. For long-term pain relief, chemical neurolysis and radiofrequency ablation (RFA) are commonly undertaken, of which RFA results in longer duration of pain relief, shorter onset and increased safety.[1] Chemical neurolysis of maxillary nerve can also result in serious complications.[2] RFA in chronic facial pain is being increasingly used with promising results.[3] We describe two patients where percutaneous RFA of peripheral maxillary nerve was undertaken without fluoroscopic/computed tomography (CT) guidance. A 60-year-old female, a diagnosed case of idiopathic trigeminal neuralgia presented with electric, sharp shooting pain of Numerical rating scale (NRS) score 6/10 in the maxillary area with frequent exacerbations for the last two years. She had inadequate pain relief with oral medications such as carbamazepine, pregabalin, baclofen and tramadol/acetaminophen. For long-term relief, RFA of maxillary nerve via percutaneous approach was planned in the block area of the out-patient department (OPD). Anaesthesia machine, resuscitation equipment, monitor and emergency drugs were available in the OPD block area. After taking consent, intravenous line was secured and monitors (pulse oximetry, non-invasive blood pressure, electrocardiography) were attached. Under aseptic precautions, a 22 G radiofrequency needle (Cosman, 10 cm length, active tip – 1 cm) was inserted via coronoid notch on right side, in supine and neutral head position, after infiltration of local anaesthesia. After hitting lateral pterygoid plate, needle was directed 2–3 mm beyond the pterygoid plate antero-superiorly towards the root of the nose [Figure 1]. To identify maxillary nerve, sensory stimulation (50 Hz, 1 mA) was used to elicit paraesthesia in maxillary area, achieved in first attempt at 0.3 mV. Motor involvement was ruled out by 2 Hz and 2 mA. 1 ml of 1% lignocaine was injected which caused paraesthesia in affected area and was followed by RFA of maxillary neve of 3 cycles at 65° for 60 s followed by injection dexamethasone 4 mg. This patient became pain-free for the next six months. All medications were reduced and tablet baclofen and tramadol were stopped.Figure 1: Infrazygomatic approach of maxillary nerve block (left); Radiofrequency generator for ablation of nerve (right)The second case was a 66-year-old male patient of idiopathic trigeminal neuralgia of one year duration with pain refractory to medical management. Maxillary nerve RFA was performed with similar methodology as above. Sensory stimulation was achieved at 0.4 mV and RFA was performed after excluding motor response. The patient was pain-free for the next eight months and his oral medications were considerably reduced. RFA of peripheral branches of the trigeminal nerve (infraorbital, supraorbital, mental and mandibular nerves) was found equally efficacious to RFA of gasserian ganglion through foramen ovale for trigeminal neuralgia; however, RFA of maxillary nerve was not undertaken in the study.[4] In the commonly practised percutaneous infrazygomatic maxillary nerve blockade,[5] a reliable block requires the patient to report paraesthesia by block needle. Electrical stimulation has reported higher sensitivity of nerve identification than paraesthesia[6] which was utilised for RFA of maxillary nerve via CT- guided percutaneous infrazygomatic approach through foramen rotundum.[7] However, this is invasive, has radiation hazards and requires special area. We propose RFA of maxillary nerve via percutaneous infrazygomatic approach and locating it by electrical stimulation. Added advantages are that it has no radiation hazards, is less invasive and it is an OPD block procedure. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Local anaesthetic techniques in endoscopic sinonasal surgery: a contemporaneous review.

Endoscopic endonasal surgery is a minimally invasive technique that has revolutionised the management of complex neurosurgical, otolaryngological, skull-base and craniofacial lesions. Traditionally performed under general anaesthetic, this study explores the growing role of local anaesthetic techniques. A contemporaneous review of modified dental techniques and intraoral anatomy provides a supportive guide for performing endoscopic sinus surgery under local anaesthetic. The practical procedures for four midfacial nerve blocks are described with relevance to endoscopic surgery under local anaesthetic. Anatomy, surgical technique and potential complications are discussed for the incisive foramen block, sphenopalatine ganglion block (via endonasal approach), maxillary nerve block (via the greater palatine foramen and the transoral lateral pterygoid plate approach) and transcutaneous approach to the pterygomaxillary fissure. Ultimately, such techniques may extend the safety and efficacy of endoscopic sinus surgery, limit surgical risk and increase satisfaction for patients, surgeons and healthcare managers alike.

The Incidence of Atlanto-Occipitalization and Additional Foramina Present in The Dry Skulls of Nepalese Population

Introduction: Atlanto-occipitalization(AOZ) is one of the congenital anomalies related to craniovertebral synostosis. The clear understanding of its anatomical features and cranial foraminal variants plays a critical role in finding the possible coping mechanism with its pathogenesis such as segmental instability or neurologic deficits.&#x0D; Objective: This study aimed to investigate the incidence of occipitalization of Atlas and related variant foramina, as the baseline awareness of these conditions among the Nepalese population is yet to be documented.&#x0D; Methodology: A retrospective study was performed for the total 86 dry skulls available in the department of Anatomy in Katmandu University of Medical Sciences, Institute of Medical Science, and B.P. Koirala Institute of Health Sciences. The skulls were examined thoroughly to evidence the occurrence of cranio-vertebral variations.&#x0D; Result: Out of 86 human adult skulls, 2 cases (2.32 %) were found with partial AOZ presenting posterior spina bifida close to the midline. Sphenoidal emissary foramen (SEF) was also observed in 17 skulls (19.76 %), an additional foramen lying anteromedial to the foramen ovale. Moreover, one of the skulls (1.16 %) was found with the presence of pterygospinous bar creating an additional foramen ‘foramen of Civinini’ in the lateral pterygoid plate of the sphenoid bone.&#x0D; Conclusion: The incidence of AOZ and pterygospinous bar seems to be quite low as compared to the cases of SEF. However, the knowledge of such variations and the presence of additional foramina carry great significance for orthopedists and neurosurgeons to have prognostic implications and an accurate surgical approach.

A Novel Injection Technique to the Lateral Pterygoid Muscle for Temporomandibular Disorders: A Cadaveric Study.

Lateral pterygoid muscle activity is associated with the pathological mechanisms of some temporomandibular disorders. The authors aimed to define and demonstrate a novel, practical, and safe technique for botulinum toxin type A injection to the lateral pterygoid muscle based on their findings. Their secondary aims were to standardize the injection pattern according to the variations of the lateral pterygoid muscle and its surrounding anatomical structures, and to establish its advantages over intraoral injection. Twenty cadaver heads were dissected. The lateral pterygoid muscle and its surrounding structures were investigated for anatomical variations. Based on these findings, a standardized extraoral injection protocol was defined and compared with the intraoral technique for accuracy and safety. The average depth of the lateral pterygoid plate from the skin surface was 49.9 ± 2.2 mm, and the mean width of the lateral pterygoid plate was 10.5 ± 3.9 mm. The extraoral injection approach based on the location of the maxillary tuberosity, tragus, and lateral pterygoid plate was consistent in all dissections for the accuracy of the intramuscular injection. In the intraoral approach, standardization of the entry point of the needle through the oral mucosa is difficult, which makes adjustment of the depth of the injection challenging while increasing the risk of neurovascular injury. The clinical significance of the lateral pterygoid muscle makes it worthwhile to implement minimally invasive treatments before considering more invasive options. The authors define a safe, accurate, and reliable approach with ease of administration in patients with temporomandibular disorders.

An Endoscopic Endonasal Nasopharyngectomy with Posterolateral Extension.

Background Invasion depth influences the choice for extirpation of nasopharyngeal malignancies. This study aims to validate the feasibility of endoscopic endonasal resection of lesions with a posterolateral invasion. As a secondary goal, the study intends to propose a classification system of endoscopic endonasal nasopharyngectomy determined by the depth of posterolateral invasion. Methods Eight cadaveric specimens (16 sides) underwent progressive nasopharyngectomy using an endoscopic endonasal approach. Resection of the torus tubarius, Eustachian tube (ET), medial pterygoid plate and muscle, lateral nasal wall, and lateral pterygoid plate and muscle were sequentially performed to expose the fossa of Rosenmüller, petroclival region, parapharyngeal space (PPS), and jugular foramen, respectively. Results Technical feasibility of endonasal nasopharyngectomy toward a posterolateral direction was validated in all 16 sides. Nasopharyngectomy was classified into four types as follows: (1) type 1: resection restricted to the posterior or superior nasopharynx; (2) type 2: resection includes the torus tubarius which is suitable for lesions extended into the petroclival region; (3) type 3: resection includes the distal cartilaginous ET, medial pterygoid plate, and muscle, often required for lesions extending laterally into the PPS; And (4) type 4: resection includes the lateral nasal wall, pterygoid plates and muscles, and all the cartilaginous ET. This extensive resection is required for lesions involving the carotid artery or extending to the jugular foramen region. Conclusion Selected lesions with posterolateral invasion into the PPS or jugular foramen is amenable to a resection via expanded endonasal approach. Classification of nasopharyngectomy based on tumor depth of posterolateral invasion helps to plan a surgical approach.

Surgical Landmarks for Parapharyngeal Internal Carotid Artery During Extended Endoscopic Surgery of Nasopharynx: A Cadaveric and Radiological Study.

Nasopharynx is a complex region situated at the center of skull surrounded by various vital neurovascular structures. Surgical access to the nasopharyngeal space poses significant challenges due to the position of the internal carotid artery (ICA). Open approaches to nasopharynx utilize the lateral to medial anatomy but the endoscopic endo-nasal approach warrants knowledge about the medial to lateral anatomy. In this study we attempted to find the consistent surgical landmarks for parapharyngeal portion of internal carotid artery at the level of nasopharynx by means of cadaveric and radiological study. Eight fresh frozen cadavers (16 sides) and 30 CT angiography (60 sides) were included in the anatomical and radiological study respectively. Superior aspect of the torus tubarius was taken as the reference point in cadaveric study and C1-C2 interspace was used as the reference point for the radiological study. The distance between the ICA to the landmarks such as fossa of Rosenmullaer, torus tubarius, medial and lateral pterygoid plates were recorded. The mean distance of ICA to the fossa of Rosenmuller was 8.5 ± 1.4mm and 9.1 ± 1.1mm in the cadaveric and radiological study respectively. The mean distance between ICA to torus tubarius was 19.8 ± 1.3mm in cadaveric and 20.6 ± 1.0mm in radiological study. The mean distance of ICA to medial and lateral pterygoid plates were 25.3 ± 1.4mm and 18.2 ± 1.4mm in the cadaveric study and 25.9 ± 1.2mm and 18.8 ± 1.3mm in the radiological study respectively. On correlating the measurements between cadaveric and radiological study, the p values were not statistically significant (p > 0.05). The closest landmark to the ICA was the fossa of Rosenmuller. ICA was located at the same sagittal plane as that of the lateral pterygoid plate. The nasopharynx is a complex anatomical region closely related to ICA. Inadvertent injury to ICA is one of the dreaded complications of nasopharyngeal surgery. Fossa of Rosenmuller is only few millimeters away from the ICA and must be treated very cautiously. During the endoscopic approach, the ICA is at the sagittal plane as of the lateral pterygoid plate. This must be kept in mind when advancing toward the ICA by keeping intact the lateral pterygoid plate when possible and one should stay in the plane of medial pterygoid plate as the ICA lies posterolateral to it. Cadaveric dissections supported by radiological data would definitely aid surgeons to successfully perform surgeries in nasopharynx.

Characteristics of the Sphenoid Bone in Crouzon Syndrome.

The goal of this study is to analyze the safety of reconstructive surgeries for Crouzon syndrome, and to understand the deformities and complications related to the surgical procedure. Thirty-nine subjects underwent preoperative computed tomographic scans were included (Crouzon, n = 19; controls, n = 20) in this study. Craniofacial cephalometric measurements were analyzed by Materialise software. The overall average distance from the pterygoid junction to the coronal plane in the patients with Crouzon syndrome was 21.34 mm (standard deviation [SD] 5.13), which was deeper than that in the controls by 35% (P = 0.000).The overall average distances between the left and right foramen ovale and pterion on the sphenoid bone in the subjects were 64.93 mm (SD 7.56) and 67.83 mm (SD 8.57), which were increased by 13% (P = 0.001) and 14% (P = 0.001) compared with those in the controls.The overall distances between the most inferior point of the left and right lateral pterygoid plate and the medial pterygoid plate in the subjects were 51.09 mm (SD 6.68) and 51.51 mm (SD 10.98), which was not statically different from the controls (P = 0.887, P = 0.991, respectively). This study characterized the surgically relevant anatomy of the sphenoidal bone. The pterygomaxillary junction is located in the posterior of the skull. Though there are some anatomical differences due to age, it is well known that the cranial cavity of the sphenoid side is likely to be enlarged in Crouzon syndrome, which may contribute to the other complications of the disease.

Skeletal width changes after mini-implant-assisted rapid maxillary expansion (MARME) in young adults.

To observe skeletal width changes after mini-implant-assisted rapid maxillary expansion (MARME) and determine the possible factors that may affect the postexpansion changes using cone-beam computed tomography (CBCT) in young adults. Thirty-one patients (mean age 22.14 ± 4.76 years) who were treated with MARME over 1 year were enrolled. Four mini-implants were inserted in the midpalatal region, and the number of activations ranged from 40 to 60 turns (0.13 per turn). CBCT was performed before MARME (T0), after activation (T1), and after 1 year of retention (T2). The mean period between T1 and T0 was 6 ± 1.9 months and between T2 and T1 was 13 ± 2.18 months. A paired t-test was performed to compare T0, T1, and T2. The correlations between the postexpansion changes and possible contributing factors were analyzed by Pearson correlation analysis. The widths increased significantly after T1. After T2, the palatal suture width decreased from 2.50 mm to 0.75 mm. From T1 to T2, decreases recorded among skeletal variables varied from 0.13 mm to 0.41 mm. This decrease accounted for 5.75% of the total expansion (2.26 mm) in nasal width (N-N) and 19.75% at the lateral pterygoid plate. A significant correlation was found between postexpansion change and palatal cortical bone thickness and inclination of the palatal plane (ANS-PNS/SN; P < .05). Expanded skeletal width was generally stable after MARME. However, some amount of relapse occurred over time. Patients with thicker cortical bone of the palate and/or flatter palatal planes seemed to demonstrate better stability.

Anatomical Variations and Relationships of the Infratemporal Fossa: Foundation of a Novel Endonasal Approach to the Foramen Ovale.

Objective Access to the infratemporal fossa (ITF) is complicated by its complex neurovascular relationships. In addition, copious bleeding from the pterygoid plexus adds to surgical challenge. This study aims to detail the anatomical relationships among the internal maxillary artery (IMA), pterygoid plexus, V 3, and pterygoid muscles in ITF. Furthermore, it introduces a novel approach that displaces the lateral pterygoid plate (LPP) to access the foramen ovale. Design and Main Outcome Measures Six cadaveric specimens (12 sides) were dissected using an endonasal approach to the ITF modified by releasing and displacing the LPP and lateral pterygoid muscle (LPTM) as a unit. Subperiosteal elevation of the superior head of LPTM revealed the foramen ovale. The anatomic relationships among the V 3 , pterygoid muscles, pterygoid plexus, and IMA were surveyed. Results In 9/12 sides (75%), the proximal IMA ran between the temporalis and the LPTM, whereas in 3/12 sides (25%), the IMA pierced the LPTM. The deep temporal nerve was a consistent landmark to separate the superior and inferior heads of LPTM. An endonasal approach displacing the LPP in combination with a subperiosteal elevation of the superior head of LPTM provided access to the posterior trunk of V 3 and foramen ovale while sparing injury of the LPTM and exposing the pterygoid plexus. The anterior trunk of V 3 traveled anterolaterally along the greater wing of sphenoid in all specimens. Conclusion Displacement of the LPP and LPTM provided direct exposure of foramen ovale and V 3 avoiding dissection of the muscle and pterygoid plexus; thus, this maneuver may prevent intraoperative bleeding and postoperative trismus.