Association between preoperative lumbar skeletal muscle index and postoperative nausea and vomiting in patients undergoing pylorus-preserving pancreatoduodenectomy: a retrospective study.

BACKGROUND: Sarcopenia is associated with postoperative complications; however, its impact on the quality of postoperative recovery, such as postoperative nausea and vomiting (PONV) and pain, remains unclear. We investigated the association of preoperative lumbar skeletal muscle mass index (LSMI) with PONV, postoperative pain, and complications. METHODS: Medical records of 756 patients who underwent pylorus-preserving pancreatoduodenectomy (PPPD) were retrospectively reviewed. The skeletal muscle areas were measured on abdominal computed tomography (CT) images. LSMI was calculated by dividing the skeletal muscle area by the square of the patient's height. We analyzed the correlations between preoperative LSMI calibrated with confounding variables and PONV scores, PONV occurrence, pain scores, rescue analgesic administration, postoperative complications, and length of hospital stay. RESULTS: The median (1Q, 3Q) LSMI was 47.72 (40.74, 53.41) cm2/m2. The incidence rates of PONV according to time period were as follows: post-anesthesia care unit, 42/756 (5.6%); 0-6 h, 54/756 (7.1%); 6-24 h, 120/756 (15.9%); 24-48 h, 46/756 (6.1%); and overall, 234/756 (31.0%). The incidence of PONV was inversely correlated with LSMI 24-48 h post-surgery and overall. LSMI and PONV scores were negatively associated 6-24 h and 24-48 h post-surgery. There was no association between LSMI and postoperative pain scores, rescue analgesic administration, complications, or length of hospital stay. CONCLUSIONS: Preoperative LSMI was associated with PONV in patients undergoing PPPD. Therefore, LSMI measured on preoperative abdominal CT can be a predictive indicator of PONV. Appropriate PONV prophylaxis is necessary in patients with low LSMI before PPPD.

Time-Resolved Electrochemical Impedance Spectroscopy of Stochastic Nanoparticle Collision: Short Time Fourier Transform versus Continuous Wavelet Transform.

This work demonstrates the utilization of short-time Fourier transform (STFT), and continuous wavelet transform (CWT) electrochemical impedance spectroscopy (EIS) for time-resolved analysis of stochastic collision events of platinum nanoparticles (NPs) onto gold ultramicroelectrode (UME). The enhanced electrocatalytic activity is observed in both chronoamperometry (CA) and EIS. CA provides the impact moment and rough estimation of the size of NPs. The quantitative information such as charge transfer resistance (Rct ) relevant to the exchange current density of a single Pt NP is estimated from EIS. The CWT analysis of the phase angle parameter is better for NP collision detection in terms of time resolution compared to the STFT method.

Observation and Analysis of Staircase Response of Single Palladium Nanoparticle Collision on Gold Ultramicroelectrodes.

Collision (or impact) of single palladium nanoparticles (Pd NPs) on gold (Au), copper (Cu), nickel (Ni), and platinum (Pt) ultramicroelectrodes (UMEs) were investigated via electrocatalytic amplification method. Unlike the blip responses of previous Pd NP collision studies, the staircase current response was obtained with the Au UME. The current response, including collision frequency and peak magnitude, was analyzed depending on the material of the UME and the applied potential. Adsorption factors implying the interaction between the Pd NP and the UMEs are suggested based on the experimental results.

Electrochemical Detection and Analysis of Various Current Responses of a Single Ag Nanoparticle Collision in an Alkaline Electrolyte Solution.

A single silver (Ag) nanoparticle (NP) collision was observed and analyzed in an alkaline solution using the electrocatalytic amplification (EA) method. Previously, the observation of a single Ag NP collision was only possible through limited methods based on a self-oxidation of Ag NPs or a blocking strategy. However, it is difficult to characterize the electrocatalytic activity of Ag NPs at a single NP level using a method based on the self-oxidation of Ag NPs. When using a blocking strategy, size analysis is difficult owing to the edge effect in the current signal. The fast oxidative dissolution of Ag NPs has been a problem for observing the staircase response of a single Ag NP collision signal using the EA method. In alkaline electrolyte conditions, Ag oxides are stable, and the oxidative dissolution of Ag NPs is sluggish. Therefore, in this study, the enhanced magnitude and frequency of the current response for single Ag NP collisions were obtained using the EA method in an alkaline electrolyte solution. The peak height and frequency of single Ag NP collisions were analyzed and compared with the theoretical estimation.

A cone-beam computed tomography evaluation of posterior available space in both arches relative to various skeletal patterns.

INTRODUCTION: This study aimed to evaluate the posterior available space (PAS) in both dental arches of adult patients with varying skeletal patterns using cone-beam computed tomography. METHODS: A sample of 114 adult patients (56 males and 58 females) was divided into 3 groups according to ANB angle and facial height ratio. Using C-mode cone-beam computed tomography images from these patients, maxillary PAS (MxPAS) and mandibular PAS (MnPAS) were measured in the distobuccal and palatal roots of the maxillary second molars and the distal roots of the mandibular second molars, respectively. The planes perpendicular to the tooth axes of the second molars in the coronal views and parallel to the posterior occlusal planes in the sagittal views were set at 3 heights of furcation, middle, and apex of the roots. For each plane, the shortest posterior distances from the roots to the inner and outer cortices were measured parallel to the furcation line connecting the furcations of the molars in the axial views. Posterior cortical bone thickness, defined as the distance from the inner cortex to the outer cortex, was measured. RESULTS: PAS was significantly greater in males than in females and in the maxilla than in the mandible (P <0.01). All MxPAS gradually increased from the furcation to the apex with significance (P <0.05), but there was no difference in MnPAS. MxPAS was significantly greater (P <0.05) in subjects with Class II and III malocclusion than subjects with Class I malocclusion, whereas MnPAS showed no difference. MxPAS showed no significant differences in facial height ratio, whereas MnPAS was significantly greater (P <0.05) at furcation in normovergent subjects than in others. Posterior cortical bone thickness was greater (P <0.001) in the mandible than in the maxilla. CONCLUSIONS: PAS was different according to sex and skeletal patterns. It would be helpful to evaluate PAS when distalizing the molars in either arch.

A Simple Risk Scoring System for Predicting the Occurrence of Aspiration Pneumonia After Gastric Endoscopic Submucosal Dissection.

BACKGROUND: Aspiration pneumonia after endoscopic submucosal dissection (ESD) is rare, but can be fatal. We aimed to investigate risk factors and develop a simple risk scoring system for aspiration pneumonia. METHODS: We retrospectively reviewed medical records of 7833 patients who underwent gastric ESD for gastric neoplasm under anesthesiologist-directed sedation. Candidate risk factors were screened and assessed for significance using a least absolute shrinkage and selection operator (LASSO)-based method. Top significant factors were incorporated into a multivariable logistic regression model, whose prediction performance was compared with those of other machine learning models. The final risk scoring system was created based on the estimated odds ratios of the logistic regression model. RESULTS: The incidence of aspiration pneumonia was 1.5%. The logistic regression model showed comparable performance to the best predictive model, extreme gradient boost (area under receiver operating characteristic curve [AUROC], 0.731 vs 0.740). The estimated odds ratios were subsequently used for the development of the clinical scoring system. The final scoring system exhibited an AUROC of 0.730 in the test dataset with risk factors: age (≥70 years, 4 points), male sex (8 points), body mass index (≥27 kg/m2, 4 points), procedure time (≥80 minutes, 5 points), lesion in the lower third of the stomach (5 points), tumor size (≥10 mm, 3 points), recovery time (≥35 minutes, 4 points), and desaturation during ESD (9 points). For patients with total scores ranging between 0 and 33 points, aspiration pneumonia probabilities spanned between 0.1% and 17.9%. External validation using an additional cohort of 827 patients yielded AUROCs of 0.698 for the logistic regression model and 0.680 for the scoring system. CONCLUSIONS: Our simple risk scoring system has 8 predictors incorporating patient-, procedure-, and sedation-related factors. This system may help clinicians to stratify patients at risk of aspiration pneumonia after ESD.

Immunomodulatory Effects of Perioperative Dexmedetomidine in Ovarian Cancer: An In Vitro and Xenograft Mouse Model Study.

BACKGROUND: The surgical stress response (SSR) causes immunosuppression which may cause residual tumor growth and micrometastasis after cancer surgery. We investigated whether dexmedetomidine affects cancer cell behavior and immune function in an ovarian cancer xenograft mouse model. METHODS: The effect of dexmedetomidine on cell viability and cell cycle was assessed using SK-OV-3 cells at drug concentrations of 0.5, 0.1, 5, and 10 µg mL-1. BALB/c nude mice were used for the ovarian cancer model with the Dexmedetomidine group (n=6) undergoing surgery with dexmedetomidine infusion and the Control group (n=6) with saline infusion for 4 weeks. Natural killer (NK) cell activity, serum proinflammatory cytokines, and cortisol were measured at predetermined time points and tumor burden was assessed 4 weeks after surgery. RESULTS: Dexmedetomidine had no effect on cell viability or cell cycle. Following a sharp decrease on postoperative day (POD) 1, NK cell activity recovered faster in the Dexmedetomidine group with significant difference vs. the Control group on POD 3 (P=0.028). In the Dexmedetomidine group, cortisol levels were lower on POD 3 (P=0.004) and TNF-α levels were lower at 4 weeks after surgery (P<0.001) compared to the Control group. The Dexmedetomidine group showed lower tumor burden at 4 weeks vs. the Control group as observed by both tumor weight (P<0.001) and the in vivo imaging system (P=0.03). CONCLUSIONS: Dexmedetomidine infusion may improve ovarian cancer surgery outcome by suppressing the SSR and stress mediator release. Further studies are needed to elucidate the mechanisms by which dexmedetomidine acts on cancer and immune cells.

Effect of Dexmedetomidine on Biochemical Recurrence in Patients after Robot-Assisted Laparoscopic Radical Prostatectomy: A Retrospective Study.

The usage of dexmedetomidine during cancer surgery in current clinical practice is debatable, largely owing to the differing reports of its efficacy based on cancer type. This study aimed to investigate the effects of dexmedetomidine on biochemical recurrence (BCR) and radiographic progression in patients with prostate cancer, who have undergone robot-assisted laparoscopic radical prostatectomy (RALP). Using follow-up data from two prospective randomized controlled studies, BCR and radiographic progression were compared between individuals who received dexmedetomidine (n = 58) and those who received saline (n = 56). Patients with complete follow-up records between July 2013 and June 2019 were enrolled in this study. There were no significant between-group differences in the number of patients who developed BCR and those who showed positive radiographic progression. Based on the Cox regression analysis, age (p = 0.015), Gleason score ≥ 8 (p < 0.001), and pathological tumor stage 3a and 3b (both p < 0.001) were shown to be significant predictors of post-RALP BCR. However, there was no impact on the dexmedetomidine or control groups. Low-dose administration of dexmedetomidine at a rate of 0.3-0.4 µg/kg/h did not significantly affect BCR incidence following RALP. In addition, no beneficial effect was noted on radiographic progression.

Predictive models for chronic kidney disease after radical or partial nephrectomy in renal cell cancer using early postoperative serum creatinine levels.

BACKGROUND: Several predictive factors for chronic kidney disease (CKD) following radical nephrectomy (RN) or partial nephrectomy (PN) have been identified. However, early postoperative laboratory values were infrequently considered as potential predictors. Therefore, this study aimed to develop predictive models for CKD 1 year after RN or PN using early postoperative laboratory values, including serum creatinine (SCr) levels, in addition to preoperative and intraoperative factors. Moreover, the optimal SCr sampling time point for the best prediction of CKD was determined. METHODS: Data were retrospectively collected from patients with renal cell cancer who underwent laparoscopic or robotic RN (n = 557) or PN (n = 999). Preoperative, intraoperative, and postoperative factors, including laboratory values, were incorporated during model development. We developed 8 final models using information collected at different time points (preoperative, postoperative day [POD] 0 to 5, and postoperative 1 month). Lastly, we combined all possible subsets of the developed models to generate 120 meta-models. Furthermore, we built a web application to facilitate the implementation of the model. RESULTS: The magnitude of postoperative elevation of SCr and history of CKD were the most important predictors for CKD at 1 year, followed by RN (compared to PN) and older age. Among the final models, the model using features of POD 4 showed the best performance for correctly predicting the stages of CKD at 1 year compared to other models (accuracy: 79% of POD 4 model versus 75% of POD 0 model, 76% of POD 1 model, 77% of POD 2 model, 78% of POD 3 model, 76% of POD 5 model, and 73% in postoperative 1 month model). Therefore, POD 4 may be the optimal sampling time point for postoperative SCr. A web application is hosted at https://dongy.shinyapps.io/aki_ckd . CONCLUSIONS: Our predictive model, which incorporated postoperative laboratory values, especially SCr levels, in addition to preoperative and intraoperative factors, effectively predicted the occurrence of CKD 1 year after RN or PN and may be helpful for comprehensive management planning.

Prediction of hypotension after postural change in robot-assisted laparoscopic prostatectomy using esophageal Doppler monitoring: a prospective observational trial.

Postural change from a steep Trendelenburg position to a supine position (T-off) during robot-assisted laparoscopic prostatectomy (RALP) induces a considerable abrupt decrease in the mean arterial pressure (MAP). We investigated the variables for predicting postural hypotension induced by T-off using esophageal Doppler monitoring (EDM). One hundred and twenty-five patients undergoing RALP were enrolled. Data on the MAP, heart rate, stroke volume index (SVI), cardiac index, peak velocity, corrected flow time, stroke volume variation, pulse pressure variation, arterial elastance (Ea), and dynamic arterial elastance were collected before T-off and at 1, 3, 5, 7, and 10 min after T-off using EDM. MAP < 60 mmHg within 10 min after T-off was considered to indicate hypotension, and 25 patients developed hypotension. The areas under the curves of the MAP, SVI, and Ea were 0.734 (95% confidence interval [CI] 0.623-0.846; P < 0.001), 0.712 (95% CI 0.598-0.825; P < 0.001), and 0.760 (95% CI 0.646-0.875; P < 0.001), respectively, with threshold values of ≤ 74 mmHg, ≥ 42.5 mL/m2, and ≤ 1.08 mmHg/mL, respectively. If patients have MAP < 75 mmHg with SVI ≥ 42.5 mL/m2 or Ea ≤ 1.08 mmHg/mL before postural change from T-off during RALP, prompt management for ensuing hypotension should be considered.Trial registration: NCT03882697 (ClinicalTrial.gov, March 20, 2019).

Hemimandibular hyperplasia treatment with condylectomy and orthodontic camouflage treatment using miniplate.

A 13-year-old growing female patient presented with hemimandibular hyperplasia of the right side, Class III hypodivergent skeletal pattern, and severe facial asymmetry. Corrective surgery was deferred until her growth had been completed. When the patient was 16 years old, a low condylectomy was performed on the hyperplastic side of her mandible to prevent its progressive condylar hyperplasia, while simultaneous orthodontic camouflage treatment was performed with the intrusion of the maxillary right posterior teeth using temporary skeletal anchorage devices without additional orthognathic surgery. A low condylectomy caused anterior and lateral open bite after the downward and backward movement of the chin, which improved Class III appearance. The intrusion of the maxillary right posterior teeth followed by compensating extrusion of the mandibular posterior teeth contributed to improve the patient's facial asymmetry with correction of the transverse occlusal plane and lip canting. After 30 months of treatment, an acceptable esthetic outcome and functional occlusion were achieved. The treatment results were well maintained for 1-year retention.

Quality of Recovery of Patients Who Underwent Curative Pancreatectomy: Comparison of Total Intravenous Anesthesia Versus Inhalation Anesthesia Using the QOR-40 Questionnaire.

BACKGROUND: There has been increasing attention on the subjective recovery of patients undergoing cancer surgery. Total intravenous anesthesia (TIVA) and inhaled anesthesia with volatile anesthetics (INHA) are safe and common anesthetic techniques. Currently, TIVA and INHA have only been compared for less invasive and less complex surgeries. This prospective randomized trial aimed to compare the quality of recovery between TIVA and INHA in patients undergoing pancreatoduodenectomy (PD) or distal pancreatectomy (DP) using the Quality of Recovery (QOR)-40 questionnaire. METHODS: We enrolled 132 patients who were randomly assigned to either the desflurane (DES) (INHA, balanced anesthesia with DES and remifentanil infusion) or TIVA (effect-site target-controlled infusion of propofol and remifentanil) groups and completed the QOR-40 questionnaire postoperatively. RESULTS: The mean global QOR-40 score on postoperative day 3 was significantly higher in the TIVA group than in the DES group. In the PD group, the total QOR-40 score was significantly higher in the TIVA group than in the DES group. Moreover, the TIVA group had significantly higher scores in the physical comfort and psychological support QOR-40 dimensions than the DES group. CONCLUSION: TIVA provides better quality of recovery scores on POD 3 for patients undergoing curative pancreatectomy. CLINICAL TRIAL REGISTRATION NUMBER: NCT03447691.

Influence of lesion and disease subsets on the diagnostic performance of the quantitative flow ratio in real-world patients.

The quantitative flow ratio (QFR) is a novel angiography-based computational method assessing functional ischemia caused by coronary stenosis. This study aimed to evaluate the diagnostic performance of quantitative flow ratio (QFR) in patients with angina and acute myocardial infarction (AMI) and to identify the conditions with low diagnostic performance. We assessed the QFR for 1077 vessels under fractional flow ratio (FFR) evaluation in 915 patients with angina and AMI. The diagnostic accuracies of the QFR for identifying an FFR ≤ 0.8 were 95.98% (95% confidence interval [CI] 94.52 to 97.14%) for the angina group and 92.42% (95% CI 86.51 to 96.31%) for the AMI group. The diagnostic accuracy of the QFR in the borderline FFR zones (> 0.75, ≤ 0.85) (91.23% [95% CI 88.25 to 93.66%]) was significantly lower than that in others (difference: 4.32; p = 0.001). The condition accompanying both AMI and the borderline FFR zone showed the lowest QFR diagnostic accuracy in our data (83.93% [95% CI 71.67 to 92.38]). The diagnostic accuracy was reduced for tandem lesions (p = 0.04, not correcting for multiple testing). Our study found that the QFR method yielded a high overall diagnostic performance in real-world patients. However, low diagnostic accuracy has been observed in borderline FFR zones with AMI, and the hybrid FFR approach needs to be considered.

Effect of volatile and total intravenous anesthesia on syndecan-1 shedding after minimally invasive gastrectomy: a randomized trial.

This study aimed to compare the effects of volatile anesthesia and total intravenous anesthesia (TIVA) on syndecan-1 shedding in patients with gastric cancer undergoing minimally invasive gastrectomy. Patients were randomly assigned to either the Volatile (n = 68) or the TIVA (n = 68) group. Anesthesia was maintained with sevoflurane/remifentanil or propofol/remifentanil in the Volatile and TIVA groups, respectively. Serum syndecan-1 was evaluated at pre-operation, end of operation, and postoperative day (POD) 1. Inflammatory markers including white blood cell (WBC) count, neutrophil-to-lymphocyte ratio (NLR), and C-reactive protein (CRP), were also measured at pre-operation, end of operation, and POD 1, 2, 3, and 5. The TIVA group showed significantly lower levels of syndecan-1 at the end of the operation compared to the Volatile group; however, no difference was seen between the groups at POD 1. The WBC count and NLR were significantly lower in the TIVA group at the end of the operation than the Volatile group, but there were no differences between the groups at POD 1, 2, 3, and 5. CRP levels were similar between the groups at all time points. In conclusion, despite TIVA being superior to volatile anesthesia in protecting endothelial glycocalyx during the operation, both did not prevent postoperative syndecan-1 shedding after gastrectomy.Clinical trial registration number: NCT04183296 (ClinicalTrial.gov, 03/12/2019).

Electrochemical Immunosensor for Human IgE Using Ferrocene Self-Assembled Monolayers Modified ITO Electrode.

The immunoglobulin E (IgE) level in serum is an important factor in the examination of allergy. Ferrocene (Fc)-modified self-assembled monolayers (SAMs) were placed on an indium tin oxide (ITO) electrode as a sensing layer for the detection of human IgE. The Fc moiety in the SAMs facilitated the electron transfer through the organic SAMs layer and electrocatalytic signal amplification. The electrochemical measurement was accomplished after the sandwich type immobilization of the receptor antibody, target human IgE, and enzyme conjugated secondary antibody. The enzyme product, p-aminophenol, was quantitatively analyzed by redox cycling via Fc. In addition, the electrochemical impedance spectroscopy (EIS) was investigated for the detection of IgE. The limit of detection (LOD), limit of quantification (LOQ), and dynamic range of the electrochemical sensor were 3 IU/mL, 10 IU/mL, and from 10 IU/mL to 100 IU/mL, respectively.

Observation of Single Nanoparticle Collisions with Green Synthesized Pt, Au, and Ag Nanoparticles Using Electrocatalytic Signal Amplification Method.

This work describes the tailored design, green synthesis and characterization of noble metal (Pt, Ag and Au) nanoparticles (NPs) using Sapinduss Mukkorossi fruit extract (SMFE) and its signal NP collision signal response, based on the principle of the electrocatatlytic amplication (EA) method. Here, the SMFE can act as both the reducing and the capping agent for the fabrication of noble nanometals. The SMFE-capped NPs was available for the observation of a single NP collision signal. Two general types of current response were observed: a staircase current response for the Pt or Au NPs, and a blip/spike current response for Ag NPs. These results demonstrated that the eco-friendly synthesized SMFE-capped NPs maintained their electrocatalytic activity, therefore they can be used for the single NP experiments and place an arena for future biosensing applications.

Sustainable ecofriendly phytoextract mediated one pot green recovery of chitosan.

Chitin and chitosan are biopolymers that have diverse applications in medicine, agriculture, food, cosmetics, pharmaceuticals, wastewater treatment and textiles. With bio-origins, they easily blend with biological systems and show exemplified compatibility which is mandatory when it comes to biomedical research. Chitin and chitosan are ecofriendly, however the processes that are used to recover them aren't ecofriendly. The focus of this work is to attempt an ecofriendly, sustainable phytomediated one pot recovery of chitosan from commercial chitin and from crab and shrimp shells and squid pen solid wastes. Graviola extracts have been employed, given the fact file that their active ingredients acetogenins actively interact with chitin in insects (resulting in its application as an insecticide). With that as the core idea, the graviola extracts were chosen for orchestrating chitin recovery and a possible chitin to chitosan transformation. The results confirm that graviola extracts did succeed in recovery of chitosan nanofibers from commercial chitin flakes and recovery of chitosan particles directly from solid marine wastes of crab, shrimp and squids. This is a first time report of a phyto-extract mediated novel chitosan synthesis method.

Transhepatic Tract Embolisation After Biliary Intervention Using n-Butyl Cyanoacrylate and Autologous Blood: A Retrospective Analysis of 42 Patients.

PURPOSE: We evaluated the safety and efficacy of transhepatic tract embolisation after a biliary intervention using n-butyl cyanoacrylate (NBCA) and autologous blood. MATERIALS AND METHODS: Between January 2017 and December 2018, 42 consecutive patients (mean age: 71 ± 15 years, 24 men) with malignant (n = 26) or benign (n = 16) biliary obstructions underwent percutaneous biliary intervention followed by tract embolisation within 2 weeks. Forty-six transhepatic tracts (4 bilateral) in 42 patients were embolised using a NBCA and lipiodol mixtures (1:1-1:2 ratios) after intraductal infusion of peripherally obtained autologous blood. The indwelling catheter diameters were 8.5-14 Fr. The median interval between percutaneous biliary drainage and tract embolisation was 10 days (range 3-14 days). Glue-cast formation via fluoroscopy and immediate complications were reviewed retrospectively in medical records. Follow-up data (median: 135, range 11-720 days) including computed tomography (CT) images (n = 17) were evaluated for delayed complications and glue-cast formation. RESULTS: Successful glue-cast formations were achieved in all 46 tracts. No patients experienced haemorrhage, and only one patient had external bile leakage. Eight patients complained of abdominal pain (numerical scale ≤ 5) immediately after embolisation, which was controlled by analgesics. Two patients had transient fever. Segmental (n = 11) or sub-segmental (n = 6) glue-cast patterns were identified along the transhepatic tract by follow-up CT. No biliary obstructions were caused by inadvertent glue spread. Fragmented glue was detected outside the stent in one patient. CONCLUSION: Transhepatic parenchymal tract embolisation with NBCA and autologous blood is a safe and feasible method for preventing bile leakage. LEVEL OF EVIDENCE: Level 4, Case Series.

Posterior Available Space for Uprighting Horizontally Impacted Mandibular Second Molars Using Orthodontic Microimplant Anchorage.

Treatment of horizontally and deeply impacted mandibular molars is challenging for both orthodontists and oral surgeons because of the limited access and anchorage control. We report on two patients who had horizontally and mesially impacted mandibular second molars (MM2s). Both patients were treated by a surgical orthodontic approach, and the crowns of the impacted teeth were brought into the arches by closed forced eruption. Mesially impacted MM2s were uprighted with orthodontic microimplants, inserted in the retromolar area, and then moved into their ideal position. The first patient was in an active growing stage, while the second patient was beyond the active growing stage. Therefore posterior available space (PAS) should be analyzed before treatment of impacted MM2s to prevent periodontal problems after uprighting of impacted teeth. If PAS is not enough for uprighting impacted MM2s, alternative treatment should be considered based on the stage of growth.