Cervical spine fusion causes limited neck mobility, a known risk factor for increased difficulty of endotracheal intubation. Cervical spine fusion surgeries are increasingly performed. The objective of this study was to determine the relationship between previous cervical spine fusion and subsequent endotracheal intubation. This retrospective study included adult patients undergoing elective surgery requiring endotracheal intubation between 2015 and 2023. We used multivariable logistic regression to identify variables independently associated with the primary outcome: requiring more than one intubation attempt. Sensitivity analyses examined the outcome within only fusion patients. We identified 938 patients, 436 with a history of cervical fusion, with 493 intubation attempts, and 502 nonfusion patients with 543 intubation attempts. The majority of the sample (91.5%) had fusion involving C3 or below, with 6.2% having a C1/C2 fusion(2.3% were missing the level of fusion). The success of the first attempt was 89.2% versus 92.6%, 8.5% versus 6.6% second attempt, and 2.3% versus 0.8% third attempt for fusion versus nonfusion patients, respectively. Requiring more than one attempt was associated with short thyromental distance, using multiple laryngoscopes, mouth trauma, and trainee status, but not with spinal fusion status (OR=1.29; 95% confident interval=079-2.12; P=0.312). Patients with a history of cervical spine fusion undergoing elective intubation experience similar rates of first intubation attempt failure compared with those without fusion when controlling for provider experience. Requiring more than one intubation attempt was associated with short thyromental distance, using multiple laryngoscopes, a trainee provider, and mouth trauma, but not a history of cervical fusion.

Vagal Reflex in Suspension Laryngoscopy: Identifying Associated Predictors and a Proactive Management Algorithm.

Higher Force Metrics Associated With Known Risk Factors for Difficult Laryngeal Exposure.

Introduction: In diabetic patients, due to “stiff joint syndrome,” the incidence of difficult laryngoscopy is higher. It can be predicted by the ‘palm print sign’ and the ‘prayer sign’. These tasks, per journal policies, can be valuable in predicting difficult laryngoscopy in non-diabetic patients as well. Material and Methods: 116 adult patients, operated under general anesthesia with endotracheal intubation, were enrolled into GROUP-D, patients with diabetes mellitus ≥5 years, and GROUP-N, patients without diabetes. Preoperatively, modified Mallampati class, thyromental distance, mouth opening, neck extension, dentition, palm print grade, and prayer sign were recorded. Cormack Lehane grade was recorded at the time of laryngoscopy. Statistical analysis was performed using Fisher's exact test. Results: Incidences of difficult laryngoscopy were 44.9% and 15.5%, in diabetics and non-diabetics, respectively. In the diabetic group, palm print grade, prayer sign, and dentition had 100% sensitivity, and thyromental distance had 98.2% specificity in predicting difficult laryngoscopy. In the nondiabetic group, the palm print sign, degree of head extension, and dentition had 100% sensitivity, and the prayer sign had 100% specificity. HbA1c levels were associated with higher palm print score and difficult laryngoscopy. Conclusion: Palm print grade and Prayer sign assessment are valuable tools to predict difficult laryngoscopy in diabetic patients, as well as equally useful in non-diabetic patients.

Airway events in pregnant patients with morbid obesity undergoing caesarean delivery under general anaesthesia: a retrospective cohort study (2015-2024).

Airway management is a critical and challenging component of emergency care, requiring skilled interventions to ensure safe intubation, particularly in difficult airway scenarios. Early identification is essential to minimize intubation attempts and reduce major airway-related complications. Although several assessment tools and scoring systems have been proposed, their effectiveness as unstructured individual predictors remains uncertain. This study aimed to develop a simple scoring system for predicting difficult airways in the emergency department (ED). To develop and preliminarily validate an innovative, easy-to-use, and uncomplicated scoring system for predicting the difficult airway in the ED. This prospective observational study was conducted in the ED of a tertiary medical center in India (January 2023-August 2025) and included 200 conscious adult patients. Five bedside predictors (body mass index (BMI), retrognathia, upper lip bite test (ULBT), thyromental distance (TMD), and hyomental distance) were assessed to develop a composite score for difficult airway prediction. The Modified Mallampati classification (MMC) (Class 3/4) was used as the reference standard for initial validation prior to assessment against the Cormack-Lehane classification. Diagnostic performance of individual predictors and the composite score was evaluated using sensitivity, specificity, predictive values, and receiver operating characteristic (ROC) analysis. Among 200 patients (n=200), 82 (n=82) were classified with a MMC of 3/4, resulting in a 41% incidence (n=82) of difficult airways. Among individual parameters, BMI >30 kg/m² demonstrated the highest individual sensitivity (79.3%), while the ULBT showed the highest specificity (94.9%). The novel scoring system achieved an overall sensitivity of 79.27% and a specificity of 71.2%. The short TMDwas the most frequently observed positive individual predictor (n=59). The McNemar test indicated a statistically significant difference in the proportions of discordant classifications between the new score and the MMC (p=0.006), suggesting they do not classify patients identically. However, the kappa coefficient of 0.522 demonstrated a moderate level of overall agreement. ROC analysis demonstrated good discriminative ability (AUC=0.752, 95% CI: 0.683-0.822, p<0.001), validating the score's diagnostic strength. This study presents a tentative confirmation of a concise, five-parameter bedside scoring tool that displays strong discriminative ability in predicting a challenging airway in the ED environment. The score outperforms individual predictors and the MMC when used on its own by synthesizing predictable clinical and anatomical variables that can be obtained in a short period of time. Its high negative predictive value makes it easy to rule out airway difficulty early and to proactively deal with airway management. To verify the applicability and clinical relevance of the suggested tool, multicenter validation is necessary.

Background: Unanticipated difficult laryngoscopy during elective surgery can lead to hypoxaemia, airway trauma, and perioperative complications; however, no single bedside airway test consistently provides high diagnostic accuracy for preoperative risk stratification. Objective: To evaluate and compare the diagnostic performance of commonly used preoperative airway assessment tests for predicting difficult laryngoscopy in adult elective surgical patients. Methods: A cross-sectional observational study was conducted at the University of Lahore Teaching Hospital among 133 patients aged 18–65 years (ASA I–III) scheduled for elective surgery under general anaesthesia with planned orotracheal intubation. Preoperative assessment included the Modified Mallampati Test (MMT), thyromental distance (TMD), inter-incisor gap (IIG), upper lip bite test (ULBT), LEMON assessment, and atlanto-occipital extension (AOE). Direct laryngoscopy findings were graded using the Cormack–Lehane (CL) system; difficult laryngoscopy was defined as CL grade III–IV. Results: Difficult laryngoscopy occurred in 15/133 patients (11.3%). MMT demonstrated the highest sensitivity (66.7%), while LEMON showed the highest specificity (77.0%). AOE yielded the highest overall accuracy (86.0%) and the strongest association with difficult laryngoscopy (restricted AOE grade III–IV: 12/15 vs 1/118; p&lt;0.001). TMD, IIG, and ULBT showed moderate predictive performance. Conclusion: No single bedside test optimally predicts difficult laryngoscopy; combining complementary assessments, particularly sensitivity-oriented screening with specificity-oriented confirmation and neck mobility evaluation, provides a more reliable preoperative approach.

IntroductionNares-to-vocal cord distance (NVD) is an important anatomical parameter for safe nasotracheal intubation and optimal positioning of nasopharyngeal devices. This study evaluated the relationship between NVD and easily obtained external body measurements in adult surgical patients.Materials and methodsWe conducted a prospective observational study in adults of both sexes undergoing elective surgery under general anesthesia. Using a fiberoptic bronchoscope, we measured NVD from the external nares to the level of the vocal cords. External measurements included height (Ht), weight (Wt), nares-ear tragus distance, nares-mandible angle distance, nares-thyroid distance, thyromental distance, sternomental distance (SMD), sternal length, arm span, and the distance from the external occipital protuberance to the tip of the C7 spinous process (OC7). We assessed correlations between NVD and these anthropometric parameters.ResultsAll external body measurements and NVD were greater in men than in women. In the overall cohort and in men, NVD showed the strongest positive correlation with OC7, followed by SMD, Ht, and Wt. In women, NVD also correlated significantly with OC7, Wt, and SMD, although the strength and consistency of these associations were lower than in men. Age and several other external measurements showed little or no meaningful correlation with NVD.ConclusionsNVD demonstrates clinically relevant associations with simple bedside anthropometric measures, particularly OC7, SMD, Ht, and Wt. These findings suggest that readily obtained external measurements may help clinicians estimate NVD when planning nasotracheal intubation or positioning nasopharyngeal devices, especially in settings where fiberoptic assessment is unavailable. Further research across broader, more diverse populations is needed to refine these relationships and support the development of practical prediction tools for airway management.

Background: Difficult intubation remains a significant concern in anesthetic practice because of its association with airway trauma, hypoxemia, and increased perioperative morbidity. Although multiple bedside airway assessment tests are routinely employed, their predictive accuracy varies, and no single parameter has proven universally reliable. This underscores the need for comparative evaluation of commonly used predictors in specific clinical populations. This study aimed to evaluate and compare the diagnostic accuracy of the modified Mallampati classification (MPC), sternomental distance (SMD), and the ratio of height to thyromental distance (RHTMD) in predicting difficult intubation, using the Intubation Difficulty Scale (IDS) as the reference standard.Methods: A prospective observational study was conducted among 57 adult patients undergoing elective surgical procedures under general anesthesia with tracheal intubation. Preoperative airway assessment included MPC, SMD, and RHTMD measurements. Laryngoscopy and intubation were performed using standard techniques, and intubation difficulty was graded using the IDS. An IDS score > 5 was considered indicative of difficult intubation. Statistical analysis comprised receiver operating characteristic (ROC) curve analysis with area under the ROC curve (AUC), logistic regression to estimate odds ratios (ORs), and correlation testing to assess associations between predictors and difficult intubation.Results: The incidence of difficult intubation in the study population was 12 (21.1%). Among the three parameters, RHTMD demonstrated the highest predictive accuracy, with an AUC of 0.84, an adjusted odds ratio (aOR) of 6.5, and a statistically significant association (p < 0.001). MPC also showed a significant predictive value (aOR 4.2, p = 0.018), followed by SMD (aOR 3.8, p = 0.032). ROC analysis confirmed the superior discriminatory ability of RHTMD compared to MPC and SMD. RHTMD had the strongest correlation (r = 0.52), followed by MPC (r = 0.41) and SMD (r = 0.38). Patients with RHTMD ≥ 25 were at significantly increased risk of difficult intubation.Conclusion: RHTMD emerged as the most accurate single predictor of difficult intubation in this cohort. However, combining multiple airway assessment parameters improved diagnostic reliability. A multimodal preoperative airway assessment strategy may enhance patient safety and reduce the risk of unanticipated difficult intubation.

Background The ability to predict a difficult airway is paramount for Anesthesiologist for devising a secure intubation strategy. The inability to secure a patent airway may precipitate life-threatening complications such as hypoxic brain injury or fatal cardiopulmonary arrest. Preoperative tests like the ULBT (Upper Lip Bite Test) and RHTMD (Ratio of Height to Thyromental Distance) are employed to predict airway management challenges. This study sought to compare the diagnostic performance of ULBT and RHTMD against the standard Intubation Difficulty Scale (IDS).Data &amp; Methods An observational, single-blind comparative study was carried out during the period of May 2022 to April 2023, among 130 individuals between the ages of 18 and 65, with an ASA classification of I or II, all scheduled for elective procedures under general anesthesia with endotracheal intubation. After obtaining ethical clearance (Ref:NMC/540/078/079), study was commenced. After informed written consent, each participant’s airway was pre-operatively evaluated using the RHTMD and ULBT. The complexity of each intubation was then objectively quantified using the IDS.Results The findings demonstrated a marked superiority of the Upper Lip Bite Test. ULBT exhibited a sensitivity of 86.36% and a specificity of 87.96%. In contrast, the Ratio of Height to Thyromental Distance showed lower efficacy, with a sensitivity of 68.18% and a specificity of 66.66%. Crucially, while both tests were comparable in their ability to correctly rule out a difficult airway (negative predictive value), the ULBT proved significantly more accurate in confirming one (positive predictive value), establishing it as the more robust predictive instrument.Conclusion The study concludes that the Upper Lip Bite Test (ULBT) is a more dependable and accurate predictor of difficult tracheal intubation, as defined by the Intubation Difficulty Scale (IDS), than the Ratio of Height to Thyromental Distance (RHTMD).

Introduction:Anticipation of a difficult airway is essential for safe anesthesia. Unanticipated difficult intubations remain a major cause of morbidity and mortality in the perioperative period. Several bedside airway assessment tests exist, but their accuracy varies.Aim:To compare the predictive value of the Modified Mallampati Test (MMT), Upper Lip Bite Test (ULBT), and Thyromental Distance (TMD) against the Cormack–Lehane (CL) grading for predicting difficult intubation.Materials and Methods:A prospective observational study was conducted on 150 ASA I–II patients (18–60 years) scheduled for elective surgery under general anesthesia. Preoperative airway assessment included MMT, ULBT, and TMD performed by a single anesthesiologist. Direct laryngoscopy was performed under standardized anesthesia, and CL grades were recorded. Grades III–IV were considered difficult intubation. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each bedside test were calculated using CL grading as the gold standard.Results:Difficult intubation was encountered in 20 patients (13.33%), with 18 graded CL III and 2 graded CL IV. Sensitivity and specificity were: MMT — 45% and 96.15%; TMD — 65% and 94.61%; ULBT — 80% and 96.92%. ULBT showed the highest predictive accuracy.Conclusion:ULBT demonstrated superior sensitivity and specificity among the tests evaluated, but no single bedside test was sufficiently accurate to predict all difficult intubations. A combination of tests is recommended for preoperative airway assessment.

Background: Airway management is the responsibility of anesthesiologists, but clinical assessment documentation is often incomplete. Difficult laryngoscopy and intubation occur in 1% to 15% of cases. Intubation is considered difficult if it takes more than ten minutes for a trained anesthesiologist to achieve successful endotracheal intubation. In Indonesia, difficult laryngeal visualization occurs in 10.1% of Malay patients. Common predictors include Mallampati classification, thyromental distance (TMD), obstructive sleep apnea (OSA), male gender, and age.Objective: This study aims to compare neck circumference (NC) to TMD as a predictor of difficulty visualizing the larynx.Methods: This diagnostic study aimed to evaluate the sensitivity and specificity of NC and TMD as predictors of difficult laryngeal visualization in patients undergoing elective surgery at Haji Adam Malik General Hospital, Medan. The sample consisted of 85 patients, aged 18 years or older, with ASA classifications of 1-2, who were undergoing general anesthesia. Exclusion criteria included limited mouth opening, acute burns, airway tumors, or anatomical abnormalities.Result: The mean age of participants was 54.97 ± 14.41 years, with a mean body mass index (BMI) of 26.63 ± 3.12 kg/m², and an average NC/TMD ratio of 6.37 ± 0.87. Patients with an NC/TMD ratio &gt; 5 had difficult intubation in 87.5% of cases, while those with an NC/TMD ratio &lt; 5 had easy intubation in 94.6% of cases. Fisher's Exact test showed a significant association (p &lt; 0.001). The NC/TMD ratio had a sensitivity of 95.45%, specificity of 85.36%, positive predictive value (PPV) of 87.5%, negative predictive value (NPV) of 94%, and an area under the curve (AUC) of 90%.Conclusion: The NC/TMD ratio is a significant and accurate predictor of difficult intubation, supporting its use as a simple, non-invasive preoperative tool.

A BSTRACT Background and Aims: Ultrasound is now widely used for predicting difficult laryngoscopy and intubation. We evaluated the clinical and ultrasound parameters with respect to difficulty of glottic visualization and need for manipulation for intubation with a videolaryngoscope and also if any correlation exists between the individual ultrasound and clinical parameters. Methods: One hundred and sixty patients aged 18–60 years, ASA physical status I and II, without any airway pathology, posted for elective surgery under endotracheal general anesthesia were included. Airway was assessed with clinical predictors (Body Mass Index (BMI), Mallampati Score, Upper Lip Bite Test (ULBT), Neck Circumference to Thyromental distance (NC/TMD) ratio) and ultrasound parameters (soft tissue thickness at the level of Hyoid bone (SHB) and vocal cords (SVC), tongue thickness (TT)). They were then correlated with the visualization of percentage of glottic opening (POGO) on videolaryngoscopy and ease of intubation. Results: All ultrasound parameters and NC/TMD predicted POGO with the highest sensitivity. For manipulation required during intubation, the optimal cutoff values were BMI &gt;26.75, Mallampati Grade of &gt; III, ULBT grade &gt; III, NC/TMD ratio &gt;4.67, SVC 0.99 cm, SHB 0.89 cm, and TT 5.92 cm. Conclusions: Airway ultrasound is a useful adjunct to clinical parameters in assessing the airway for videolaryngoscopy and intubation. NC/TMD and SVC predicted the need for manipulation with the highest accuracy. The BMI and Mallampati best correlated with tongue thickness, while the NC/TMD best correlated with the SVC and SHB.

IntroductionDifficult intubation is one of the most challenging scenarios to deal with due to increased morbidity and mortality. Machine learning systems can help predict this process in advance. This study aimed to predict whether patients had difficult intubation using machine learning programs for anthropometric and ultrasonographic measurements taken for preoperative airway assessment.MaterialmethodPatients over 18 years of age with American Society of Anesthesiologists (ASA) scores I–III who underwent general anesthesia were included. Patients with a history of head/neck surgery, planned thyroidectomy, congenital or acquired airway anomalies morbidly obese patients with BMI > 40 or a known difficult airway were excluded. Preoperative modified mallampati test score and other anthropometric measurements (thyromental distance, neck circumference, mouth opening, sternomental distance) were recorded. Ultrasonographic measurements included the distance from skin to hyoid bone, skin to epiglottis, skin to vocal cords (anterior commissure), skin to trachea, MTT and hyomental distances in neck extension and neutral positions. The dataset was analyzed via eight different machine learning algorithms.ResultsWe obtained data from 329 patients (62 difficult intubation cases). The Support Vector Machine algorithm achieved the highest performance, with an accuracy of 89.39%, a negative predictive value of 92.7%, and a positive predictive value of 72.7%. Among all evaluated parameters, the modified mallampati score, neck circumference, skin to epiglottic distance and tongue thickness were the strongest predictors of difficult intubation.ConclusionThe ability of individual bedside tests, which are commonly used, to predict difficult intubations is limited. Our study demonstrates that incorporating ultrasonographic measurements into a machine learning model, in addition to clinical airway assessments, improves predictive accuracy. Integrating our predictive model into a mobile app could provide a rapid and objective tool for preoperative airway assessment to identify difficult airways and improve patient safety in anesthesia settings.Trial registrationProspective Observational.

Background: Anthropometric tests and scales used to predict difficult intubation in people with obesity have limited sensitivity and specificity. A thyromental height test (TMHT) is based on the height between the anterior border of the thyroid cartilage and the anterior border of the mentum. Objectives: The aim of this study was to assess the usefulness of TMH in the prediction of difficult intubation in patients with obesity scheduled for elective surgical procedures. Methods: A prospective, observational cohort study in adult patients with BMI ≥ 30 kg⋅m−2 scheduled for elective surgical procedures under general anesthesia, direct laryngoscopy, and intubation was conducted in a university hospital between June 2020 and June 2021. The primary outcome measure was thyromental height, and the secondary outcome measures were thyromental distance (TMD), sternomental distance (SMD), score in the modified Mallampati test (MMT), Cormack–Lehane grade (CL), neck circumference (NC), and mouth opening (MO) distance. As a secondary outcome, a composite score was developed and analyzed for its predictive performance. Results: In 77 patients (56 females, 72.7%) aged 43.21 ± 9.39 years with a mean BMI of 37.18 (34.6–42.8) kg⋅m−2, difficult intubation was found in 18 patients (23.38%). Sleep apnea was present in 14 (23.75) patients with easy intubation vs. 9 (50%) patients with difficult intubation (p = 0.033). There were no statistically significant differences in thyromental height test, thyromental distance, neck circumference, and mouth opening scores. Male sex, TMD ≤ 175 mm, and MO ≤ 60.5 mm were predictors of difficult laryngoscopy. The OPERA Score (range 0–5) demonstrated superior predictive value (AUC = 0.8 p < 0.01), outperforming its individual components. Conclusions: Male sex, TMD ≤ 175 mm, and MO ≤ 60.5 mm are predictors for difficult laryngoscopy in patients with obesity. The results of our study indicate that TMH may not be a good predictor of difficult intubation in patients with obesity. However, when integrated into a composite score, it contributes meaningfully to a multifactorial risk assessment.

BackgroundPregnancy-related anatomical and physiological changes, such as mucosal edema and increased oxygen demand, heighten risk of difficult airway, especially under general anesthesia. This study compared effects of spinal and general anesthesia on postoperative airway assessment tests in cesarean deliveries. We hypothesized upper airway changes can occur depending on anesthesia technique.Material/MethodsThis prospective observational study included 100 pregnant women undergoing elective cesarean delivery. Patients were divided into 2 groups according to anesthesia type: spinal (n=64) and general (n=36). Five basic airway assessment tests (modified Mallampati score, thyromental distance, sternomental distance, neck circumference, and upper lip bite test) were performed preoperatively and 1, 6, and 24 h after surgery (T1–T4).ResultsNo significant changes were observed over time in the spinal group (all P>0.05), with Mallampati scores remaining stable from T1 to T4 (mean T1: 1.7±0.6; T4: 1.8±0.5). In contrast, general anesthesia group showed a significant increase in Mallampati scores at T2 (T1: 1.7±0.6 vs T2: 2.4±0.7, P<0.001). Postoperative nausea and vomiting were more frequent in the general anesthesia group (27.8% vs 10.9%, P=0.016). In hemodynamic evaluation, systolic and diastolic blood pressure values were significantly higher at the 2nd and 5th minutes in the general anesthesia group (2nd min SBP: 128.4±20.6 mmHg vs 114.5±17.4 mmHg; 5th min SBP: 121.4±15.6 mmHg vs 107.1±14.7 mmHg; both P<0.001).ConclusionsThe significant increase in Mallampati scores after general anesthesia highlights the potential for upper airway edema due to intubation. Anticipating this risk is important for airway safety in the early postpartum period.

Various tests have been developed to predict difficult airway during preoperative examination, but none has presented an adequate degree of accuracy. This study investigates novel mandibular structures and angles for evaluation as potential predictor of difficult laryngoscopy. Following Ethics Committee approval, 1001 patients scheduled for elective surgeries under general anesthesia with oral intubation were included in this prospective study. Difficult laryngoscopy was defined as a Cormack-Lehane grade III or IV view. Standard predictive tests - including neck circumference, thyromental distance, sternomental distance, Modified Mallampati Test (MMT), mouth opening, and upper lip bite test - were evaluated alongside two novel parameters: the "mandibular profile angle" and "inter-pterygoid distance." The sensitivity and specificity of the Modified Mallampati Test (MMT) for predicting difficult laryngoscopy were 46% and 91%, respectively, with a positive predictive value (PPV) of 51% and a negative predictive value (NPV) of 89%. In contrast, the "mandibular profile angle" demonstrated a sensitivity of 83%, specificity of 86%, PPV of 55%, and NPV of 96%. The "inter-pterygoid distance" showed similar accuracy, with a sensitivity of 82%, specificity of 88%, PPV of 58%, and NPV of 96%. The area under the curve (AUC) values were 0.89 for the "mandibular profile angle" and 0.90 for the "inter-pterygoid distance." The optimal cut-off for predicting difficult laryngoscopy was 107.75° for the "mandibular profile angle" and 13.05 cm for the "inter-pterygoid distance." These findings suggest that using mandibular structures in preoperative assessments to anticipate and prepare for difficult laryngoscopy scenarios provides reliable threshold values that may improve patient safety and procedural outcomes. The introduction of novel measurements, specific to mandibular structure assessment, carries the potential to initiate a distinct approach in predicting difficult laryngoscopy. By integrating these measurements with existing bedside tests, a substantial enhancement in the accuracy and robustness of predictive evaluations may be reached.

Introduction. A comprehensive airway assessment requires an understanding of the anatomical features of the neck and upper airway. Accurately predicting a potentially difficult airway is a multifactorial challenge, dependent on patient-related factors, clinical context, and the anesthesiologist’s proficiency. Failure to anticipate a difficult airway remains a common cause of anesthesia-related complications.The objective was to evaluate the relationship between the neck circumference to thyromental distance ratio (NC/TMD) and the incidence of difficult intubation in adult patients scheduled for elective surgeries under general anesthesia.Materials and method. This study included 100 patients undergoing elective surgeries under general anesthesia with endotracheal intubation of ASA grades I and II. Patients were examined preoperatively and intraoperatively. Data collection using the patient proforma which includes the demographic data, body mass index (BMI), NC/TMD ratio, thyromental distance (TMD), and Modified Mallampati Test (MMT). Statistical software (SPSS 20.0) was used for statistical analyses of the data.Results. In cases of difficult intubation, TMD was significantly lower (mean = 6.07 cm, SD = 0.892) than in its absence (7.31 cm, SD = 0.877, P = 0.02994). The values of the ratio between neck circumference and TMD in individuals without difficult intubation were lower: 4.78 (SD = 0.466) versus 5.71; SD = 0.183 (P &lt; 0.001).Conclusion. The NC/TMD ratio is a simple, effective, and non-invasive predictor of difficult intubation. It demonstrates superior sensitivity and specificity compared to NC and MMT. Routine incorporation of this measurement in preoperative airway assessment could improve the safety of anesthesia.

Airway management is a cornerstone of safe anesthesia practice, and failure to anticipate a difficult airway can result in life-threatening complications. The Modified Mallampati Score (MMS) and Thyromental Distance Test (TMDT) are among the most widely used preoperative predictors. However, when used individually, their predictive accuracy remains variable. Combining these tests may improve diagnostic performance and support safer airway management in surgical patients. Objective: To evaluate and compare the sensitivity, specificity, and predictive values of MMS and TMDT individually and in combination for predicting difficult intubation in apparently normal patients undergoing elective surgery. Methods: This comparative observational study enrolled 150 patients with ASA physical status I or II scheduled for elective procedures under general anesthesia. Preoperative airway assessment was performed using MMS and TMDT, with Cormack–Lehane (CL) grading during laryngoscopy serving as the gold standard. Demographic data, surgical specialty, intubator experience, and the use of special equipment were recorded. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each test and their combination. Results: MMS showed a sensitivity of 42.3%, specificity of 92.0%, PPV of 52.3%, and NPV of 88.4%. TMDT had a sensitivity of 23.07%, specificity of 92.0%, PPV of 37.5%, and NPV of 85.1%. The combined use of MMS and TMDT improved specificity to 98.4%, PPV to 66.7%, and maintained a high NPV of 84.8%, though sensitivity decreased to 15.4%. Difficult intubations were more frequent in females (80.8%) and general surgery cases (100%), while the use of special equipment was significantly associated with difficulty (p = 0.000). Conclusion: While neither MMS nor TMDT alone offers both high sensitivity and specificity, their combined use enhances diagnostic accuracy and should be considered a valuable component of routine preoperative airway assessment.

Computed Tomography-Based Predictors of Difficult Intubation in Oral and Maxillofacial Surgery Patients.