Minimally invasive orthognathic surgery: a systematic review

Minimally invasive techniques are currently applied in many oral and maxillofacial surgical procedures, including orthognathic surgery. A systematic review on the application of potentially minimally invasive procedures in orthognathic surgery was performed to provide a clear overview of the relevant published data. Articles in English on minimally invasive orthognathic procedures, published in the scientific literature, were obtained from the PubMed, Embase, and Cochrane Library databases, and an additional manual search (revised 31 December 2016). After screening the abstracts and applying the eligibility criteria, 403 articles were identified. All articles reporting the potential for minimally invasive orthognathic surgery were included (n = 44). The full papers were evaluated in detail and categorized as articles on a minimally invasive surgical approach (n = 4), endoscopically assisted orthognathic procedures (n = 17), or the use of a piezoelectric device in orthognathic surgery (n = 25); two articles were each included in two categories. Although a small incision and minimal dissection is the basic principle of a minimally invasive technique, most articles (90.9%) reported the endoscope and piezoelectric instrument as important tools in minimally invasive orthognathic surgery. Evidence from available studies suggests that patients undergoing minimally invasive orthognathic surgery have less morbidity and make a faster recovery. Further research should aim to obtain higher levels of evidence.     

The impact of smoking on surgical complications after head and neck reconstructive surgery with a free vascularised tissue flap: a systematic review and meta-analysis

Reconstructive surgery with a free vascularised tissue flap is indicated in large defects in the head and neck region, which arise mostly because of head and neck cancer. Tobacco smoking is a major risk factor for head and neck cancer, and many patients undergoing reconstructive surgery in the head and neck have a history of smoking. The objective of this meta-analysis was to determine the impact of smoking on surgical complications after head and neck reconstructive surgery with a free vascularised tissue flap. A systematic review was undertaken for articles reporting and comparing the incidence of overall surgical complications after reconstructive surgery with a free vascularised tissue flap between smokers and nonsmokers. Relevant articles were searched using PubMed, Cochrane, and Embase databases, and screened for eligibility according to the PRISMA guidelines. The risk of bias analysis was conducted using the Newcastle-Ottawa quality assessment scale. A meta-analysis was performed to quantitatively compare the incidence rate of overall surgical complications, flap failure, surgical site infection, fistula, and haematoma between smokers and nonsmokers using OpenMetaAnalyst (open source) software. Only qualitative analysis was performed for wound dehiscence, bleeding, nerve injury, and impaired wound healing. Forty-six articles were screened for eligibility; 30 full texts were reviewed, and 19 studies were included in the quantitative meta-analysis. From the 19 studies, 18 were retrospective and 1 was a prospective study. In total, 2155 smokers and 3124 nonsmokers were included in the meta-analysis. Smoking was associated with a significantly increased risk of 19.12% for haematoma (95% Confidence Interval (CI): 4.75–33.49; p < 0.01), and of 4.57% for overall surgical complications (95% CI: 1.97–7.15; p < 0.01). No significant difference in risk was found for flap failure (95% CI: ?4.33–9.90; p = 0.44), surgical site infection (95% CI: ?0.88–2.60; p = 0.33) and fistula formation (95% CI: ?3.81–3.71; p = 0.98) between smokers and nonsmokers. Only for flap failure was a significant heterogeneity found (I² = 63.02%; p = 0.03). Smoking tobacco was significantly associated with an increased risk of overall surgical complications and haematoma, but did not seem to affect other postoperative complications. Encouraging smoking cessation in patients who need reconstructive head and neck surgery remains important, but delaying surgery to create a non-smoking interval is not needed to prevent the investigated complications. More high-quality retrospective or prospective studies with a standardised protocol are needed to allow for definitive conclusions.     

Submental intubation in oral and maxillofacial surgery: a systematic review 1986–2018

Submental intubation is a low-risk alternative to tracheostomy when nasotracheal or orotracheal intubation is not appropriate. To improve the selection of patients and clinical outcomes we have explored published papers on submental intubation in oral and maxillofacial surgery, and included a proposal for a decision pathway. Systematic searches of PubMed, Scopus, and Cochrane databases for papers published between 1986 and 2018 yielded 116 eligible articles (one randomised controlled trial, 61 case series, 40 case reports, six surgical techniques, and eight letters) that included 2 229 patients. Measured outcomes were the indications, techniques, devices used, time taken to complete the procedure, and complications. Indications were trauma (81%), orthognathic surgery (15%), disease (2%), and cosmetic surgery (1%). Technical preferences were for a one-tube (84%) over a two-tube technique (6%), and a paramedian (52%) over a median incision (33%). The preferred device was a reinforced endotracheal tube (85%). The mean (range) intubation time was 10 (2–37) minutes. The complication rate was 7% (n = 152), the most common being superficial skin infection (n = 54), hypertrophic scarring (n = 18), and damage to the tube apparatus (n = 15). Submental intubation has minimal complications, takes a short time to do, and it is a useful alternative to tracheostomy in some oral and maxillofacial operations. More robust evidence regarding the selection of patients, modifications to the technique, and a comparison of risk with that of tracheostomy, are needed for further evaluation of its feasibility.     

Head and neck cancer surgery in an elderly patient population: a retrospective review

Should advanced age be a contraindication to the surgical management of head and neck cancer patients? A retrospective chart review was performed of patients aged ≥80 years treated surgically for a head and neck malignancy during the period 1996–2011 in a tertiary care cancer centre. The average follow-up was 32 months. Fifty-three patients were identified (mean age 85 years). Cardiovascular disease was the most prevalent co-morbidity (43%). Forty-five patients (85%) had oral cavity/oropharynx squamous cell carcinoma. Surgeries performed included 40 neck dissections and 12 microvascular free flaps. The average length of hospital stay (LOS) was 6.4 days. An increased LOS was significant in patients requiring free flap reconstruction (P < 0.01). There were no perioperative deaths or free flap failures. The most common postoperative complications were cardiovascular (n = 8), infection (n = 10), and delirium (n = 6). Thirty-four patients were discharged directly home. Free flap reconstruction did not adversely affect discharge disposition (P > 0.05). More than 75% of patients did not report any major limitations to their activities of daily living. Major head and neck surgical procedures can be tolerated by patients of advanced age using careful patient selection. Age alone should not be a primary factor in the management of head and neck cancer patients.     

Comparison between computer-guided and freehand dental implant placement surgery: A systematic review and meta-analysis

The purpose of this systematic review was to compare computer-guided (fully guided) and freehand implant placement surgery in terms of marginal bone loss, complications, and implant survival. This review followed the PRISMA guidelines and was registered in the PROSPERO database (CRD42019135893). Two independent investigators performed the search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published up to April 2020 and identified 1508 references. After a detailed review, only four studies were considered eligible. These studies involved a total of 154 patients with 597 dental implants and a mean follow-up period of 2.25 years. There was no difference between computer-guided surgery and freehand surgery in terms of the marginal bone loss (mean difference ?0.11 mm, 95% confidence interval (CI) ?0.27 to 0.04 mm; P = 0.16), mechanical complications (risk ratio (RR) 0.85, 95% CI 0.36–2.04; P = 0.72), biological complications (RR 1.56, 95% CI 0.42–5.74; P = 0.51), and implant survival rate (RR 0.53, 95% CI 0.11–2.43; P = 0.41). This meta-analysis demonstrated that both computer-guided and freehand surgeries yielded similar results for marginal bone loss, mechanical and biological complications, and implant survival rate.     

Chimeric posterior tibial artery flap: clinical application in oral and maxillofacial reconstruction

The objective was to describe the utility of the chimeric posterior tibial artery flap (CPTAF) in the restoration of compound defects in the oral and maxillofacial region. Patients who underwent head and neck reconstruction using a CPTAF between February 2018 and February 2019 were included. Special consideration was given to the distribution of septocutaneous perforators (SPs), indications, flap survival, and complications. Nine patients were included. All flaps survived. One patient developed a surgical site infection, which was managed conservatively. The CPTAF was raised as a bipaddle skin flap without muscle (n = 1), with the gastrocnemius muscle (n = 6), or with the soleus muscle (n = 2). The number of SPs ranged from three to five (mean 4 ± 0.8). The SPs were mostly located between 4 cm and 20 cm proximal to the medial malleolus (mean 9.5 ± 3.8 cm). The skin paddle was used to reconstruct skin or mucosal defects, whereas the muscle part was used to fill the dead space (n = 7) or to support the orbital contents (n = 1). The donor site healed with no associated functional complications. The CPTAF is a good option for the restoration of composite tissue defects in the head and neck region. It offers flexibility during flap inset and provides the appropriate bulk to repair defects in multiple planes.     

Extracraniofacial anomalies in Treacher Collins syndrome: A multicentre study of 248 patients

Treacher Collins syndrome (TCS) is a congenital malformation of the craniofacial structures derived from the first and second pharyngeal arches. The craniofacial deformities are well described in the literature. However, little is known about whether there are associated extracraniofacial anomalies. A retrospective study was conducted using data from four craniofacial units. Medical charts were reviewed for the presence and type of extracraniofacial anomalies, as well as age at diagnosis. A possible correlation between the severity of the phenotype and the presence of extracraniofacial anomalies was assessed using the Hayashi classification. A total of 248 patients with TCS were identified; 240 were confirmed to have TCS, of whom 61 (25.4%) were diagnosed with one or more extracraniofacial anomalies. Ninety-five different extracraniofacial anomalies were found; vertebral (n = 32) and cardiac (n = 13) anomalies were most frequently seen, followed by reproductive system (n = 11), central nervous system (n = 7), and limb (n = 7) anomalies. No correlations between tracts were found. Extracraniofacial anomalies were more prevalent in these patients with TCS compared to the general population (25.4% vs 0.001–2%, respectively). Furthermore, a positive trend was seen between the severity of the syndrome and the presence of extracraniofacial anomalies. A full clinical examination should be performed on any new TCS patient to detect any extracraniofacial anomalies on first encounter with the craniofacial team.     

Incidence of bleeding after minor oral surgery in patients on dual antiplatelet therapy: a systematic review and meta-analysis

Bleeding is a feared complication of minor oral surgery in patients on treatment with antiplatelet agents and there is no agreed strategy regarding the cessation or not of antiplatelet treatment. The aim of this systematic review was to evaluate bleeding with minor oral surgery in patients on dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT), or no antiplatelet therapy (no APT). The PubMed, Embase, Web of Science, and Cochrane Library databases were screened. Sixteen studies were included. DAPT was continued in all studies. The perioperative bleeding risk was significantly higher for DAPT than for SAPT (risk ratio (RR) 10.16, P =  0.010; risk difference (RD) 0.35, P =  0.269), but not higher compared to no APT (RR 6.50, P =  0.057; RD 0.19, P =  0.060). The postoperative bleeding risk was significantly elevated for DAPT compared to SAPT (RR 2.61, P =  0.010) and no APT (RR 3.63, P =  0.035), but only by 1% (RD 0.01, P =  0.103) and 1% (RD 0.01, P =  0.421), respectively. Clinically, this may be considered quite similar. Additionally, local haemostatic measures could control all reported bleeding and no lethal events occurred. Therefore, DAPT interruption is not advised before minor oral surgery.     

Prognosis for craniofacial fibrous dysplasia after incomplete resection: age and serum alkaline phosphatase

Complete resection is usually impossible for fibrous dysplasia (FD) involving the cranial base. Incomplete resection could be followed by regrowth of FD, but there is no method for indicating disease progress. Serum alkaline phosphatase (ALP) is significantly high in patients with FD. The authors investigate the relationship between ALP, progress of FD, and age at surgery. 18 patients with craniofacial FD were separated into 3 groups: Group A, complete resection; Group B, incomplete resection followed by regrowth of FD; and Group C, incomplete resection but no regrowth of FD. Medical records and CT scans were reviewed retrospectively. ALP levels were obtained preoperatively, postoperatively and every year during follow-up. The relation between ALP and regrowth and that between age at surgery and regrowth were investigated. There was no recurrence in Group A (n = 4). Regrowth in Group B (n = 7) was preceded by an abrupt increase in ALP. In Group C (n = 7), no regrowth was observed and ALP was maintained within the normal range. 6 patients (85%) in Group B and 2 (28%) in Group C were under 17 years old. The results revealed that the level of postoperative serum ALP could be a reliable marker for predicting the progress of craniofacial FD.     

Evaluation of the efficacy of celecoxib and ibuprofen on postoperative pain,swelling, and mouth opening after surgical removal of impacted third molars: a randomized,controlled clinical trial

The objective of this study was to compare the efficacy of celecoxib and ibuprofen in reducing postoperative sequelae following the surgical removal of impacted mandibular third molars. Ninety-eight subjects who needed surgical extraction of an impacted mandibular third molar were selected for the study. All subjects were randomly allocated to receive one of the following treatments twice a day for 5 days after surgery: placebo (n = 32), ibuprofen (n = 33), or celecoxib (n = 33). The primary outcome chosen was postoperative pain, which was evaluated using the visual analogue scale (VAS) score recorded by each patient. The secondary outcomes chosen were changes in postoperative swelling and maximum mouth opening values compared to preoperative ones. Compared to placebo, treatment with celecoxib and ibuprofen resulted in improvements in the primary outcome. Furthermore, when compared to the other groups, patients in the celecoxib group showed a significant reduction in postoperative pain scores at 6 h (P < 0.001), 12 h (P = 0.011), and 24 h (P = 0.041) after surgery. Regarding swelling and maximum mouth opening values, there were no significant differences between the groups at each follow-up session. This study demonstrated that treatment with celecoxib decreased the incidence and severity of postoperative pain following third molar surgery compared to ibuprofen and placebo.     

Use of patient-reported outcome measures in oral and maxillofacial trauma surgery: a review

In the UK, about one person/100/year sustains a facial injury, so trauma surgery accounts for a considerable part of the caseload in oral and maxillofacial surgery (OMFS). Patient-reported outcome measures (PROM) allow for patient-centred assessment of postoperative outcomes, but to our knowledge, most research in OMFS trauma does not currently include them. To investigate their use, we searched Medline to find relevant studies that reported outcomes from inception in January 1879 to August 2016. Those not in the English language and those that did not report operations were excluded. We retrieved 416 articles, of which 21 met the inclusion criteria (five randomised controlled trials and 16 cohort studies) yielding 16 outcome measures. Most of these had been devised by authors (eight studies), four studies reported use of the Geriatric Oral Health Assessment Index, and three the Nasal Obstruction Symptom Evaluation. Most were used in studies on mandibular surgery (n = 13), followed by those on nasal and facial surgery (n = 3 each). There is a great heterogeneity in the use of these assessments in OMF trauma. In view of their increasing importance compared with simpler objective measures that may not be relevant to the patients’ own perception, more research is needed to establish which of them can be used to measure the QoL of patients treated for OMF trauma.     

Orthognathic surgery with or without induced hypotension

This study involved a retrospective evaluation of patients subjected to surgery for dentofacial deformities treated without induced controlled hypotension (group I, n = 50) and a prospective evaluation of patients who were subjected to surgery under hypotensive general anaesthesia (group II, n = 50). No statistical differences were found between the study groups with regard to the duration of surgery. However, there were statistically significant differences in the need for blood transfusion and the occurrence of bradycardia during the maxillary down-fracture. Hypotensive anaesthesia decreased the need for a blood transfusion and the occurrence of bradycardia, and is therefore considered highly beneficial for patients undergoing orthognathic surgery.     

Role of computed tomography angiography in the diagnosis of vascular stenosis in head and neck microvascular free flap reconstruction

The aim of this study was to evaluate the role of computed tomography angiography (CTA) in the diagnosis of vascular stenosis at the vascular pedicle of head and neck microvascular free flaps. A prospective study was done of 65 consecutive patients (49 male, 16 female; mean age 55 years) who had undergone head and neck microvascular free flap reconstruction. All patients underwent 64-slice CTA of the carotid artery. Post-processing with volume rendering reconstruction of CTA images was done. There was excellent inter-observer agreement (weighted kappa = 0.82, 95% confidence interval (CI) 0.74–0.93) in grading of the degree of vascular stenosis. The true sensitivity of CTA for diagnosis of stenosis of the vascular pedicle to the flap was 63% (95% CI 63–100%). Patients with failed flaps showed complete occlusion (n = 2) on CTA and underwent a replacement flap procedure. Patients with failing flaps showed severe stenosis (n = 6) of the vascular pedicle on CTA and underwent revision surgery. There was no change in the degree of stenosis on follow-up CTA for patients with moderate stenosis (n = 9). CTA is a reliable, non-invasive, high-quality imaging tool for the diagnosis and grading of vascular stenosis of the vascular pedicle of head and neck microvascular free flaps.     

Three-dimensional analysis of nasolabial soft tissue changes after Le Fort I osteotomy: a systematic review of the literature

A systematic review was conducted to investigate the three-dimensional (3D) effect of Le Fort I osteotomy on the nasolabial soft tissues. The literature search was conducted using the MEDLINE (accessed via PubMed), Embase, and Cochrane electronic databases until January 2018. A total of 333 studies were identified (PubMed, n = 292; Embase, n = 41; Cochrane Library, n = 0). Seventeen met the inclusion criteria. The studies were essentially retrospective. The risk of bias was considered high in 15 studies, medium in one study, and low in one study. 3D soft tissue analysis was performed at least 6 months after surgery (mean 8.3 months). The main image acquisition technique reported was cone beam computed tomography (CBCT), associated or not with 3D photography. Approximately 50% of the studies performed two-jaw surgery, 25% performed maxillary surgery only, and the other 25% included heterogeneous intervention groups. The most reported nasolabial changes were anterior and lateral movements of the nasomaxillary soft tissues and upper lip, together with anterior and superior movement of the nasal tip. The alar cinch suture and V–Y closure technique seemed to have little effect in counteracting the undesirable postoperative nasolabial changes. CBCT superimposition presented a reliable 3D assessment for simultaneous measurement of skeletal and soft tissue changes.     

Increased tracheostomy rates in head and neck cancer surgery during the COVID-19 pandemic

Surgical practice during the coronavirus disease 2019 (COVID-19) pandemic has changed significantly, without supporting data. With increasing experience, a dichotomy of practice is emerging, challenging existing consensus guidelines. One such practice is elective tracheostomy. Here, we share our initial experience of head and neck cancer surgery in a COVID-19 tertiary care centre, emphasizing the evolved protocol of perioperative care when compared to pre-COVID-19 times. This was a prospective study of 21 patients with head and neck cancers undergoing surgery during the COVID-19 pandemic, compared to 193 historical controls. Changes in anaesthesia, surgery, and operating room practices were evaluated. A strict protocol was followed. One patient tested positive for COVID-19 preoperatively. There was a significant increase in pre-induction tracheostomies (28.6% vs 6.7%, P = 0.005), median hospital stay (10 vs 7 days, P = 0.001), and postponements of surgery (57.1% vs 27.5%, P = 0.01), along with a significant decrease in flap reconstructions (33.3% vs 59.6%, P = 0.03). There was no mortality and no difference in postoperative morbidity. No healthcare personnel became symptomatic for COVID-19 during this period. Tracheostomy is safe during the COVID-19 pandemic and rates have increased. Despite increased rescheduling of surgeries and longer hospital stays, definitive cancer care surgery has not been deferred and maximum patient and healthcare worker safety has been ensured.     

Second salvage surgery with extended vertical lower trapezius island myocutaneous flap reconstruction for advanced re-recurrent oral and oropharyngeal squamous cell carcinoma

The purpose of this study was to evaluate the outcomes of second salvage surgery with extended vertical lower trapezius island myocutaneous flap (TIMF) reconstruction for patients with re-recurrent oral cavity and oropharyngeal squamous cell carcinoma (SCC). The subjects were 23 patients with advanced re-recurrent oral and oropharyngeal SCC undergoing second salvage surgery and reconstruction with a TIMF. A TIMF with a skin paddle measuring 6 cm × 7 cm to 10 cm × 22 cm was used to reconstruct the major defects. Three patients experienced minor complications: minor flap failure (n = 1), wound dehiscence at the donor site (n = 1), and an orocutaneous fistula (n = 1). The patients were followed for 3–72 months. Fifteen patients were alive with no evidence of disease, two were alive with disease, and six died of local recurrence or distant metastases. Second salvage surgery remains an effective treatment modality for select patients with advanced re-recurrent oral and oropharyngeal SCCs, and the extended vertical lower TIMF is a large, simple, and reliable flap for reconstructing the major defect following second salvage surgery.     

Accuracy of maxillary repositioning in two-jaw surgery with conventional articulator model surgery versus virtual model surgery

The purpose of this study was to compare the accuracy of maxillary repositioning using the recently introduced computerized virtual model surgery (VMS) with conventional articulator model surgery (AMS). Forty-two patients who had undergone bimaxillary surgery were investigated retrospectively in this study. The patients were divided into two groups: conventional AMS (n = 23) and VMS (n = 19) for intermediate splint fabrication in maxillary positioning. Planned surgical movements and actual postsurgical changes of the lateral and frontal cephalometric measurements were compared. Although variations from the planned surgical movements were relatively small, both methods had statistically significant errors in some of the linear measurements. Both groups had a similar range of errors. The overall absolute mean discrepancy between the planned and actual surgical movements for the linear measurements was 1.17 mm (0–3.6 mm) in AMS and 0.95 mm (0–3.2 mm) in VMS. Of the total measurements, measurements reflecting a surgical discrepancy of more than 2 mm or 2° comprised 12.0% of the cases in AMS and 7.9% in VMS. The surgical accuracy of maxillary positioning with VMS was comparable to conventional AMS. Because VMS has the definitive advantage of eliminating the complex laboratory step and shortening the laboratory time, this can be accepted as an alternative to AMS.     

Accuracy of virtual planned surgery versus conventional free-hand surgery for reconstruction of the mandible with osteocutaneous free flaps

Virtual surgical planning (VSP) promises higher accuracy, efficiency, and superior patient outcomes, helping normalize outcomes from surgeons of different experience levels. A systematic review was conducted in agreement with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The objective was to evaluate the accuracy and secondarily efficiency of VSP compared with free-hand surgery, for mandibular reconstruction with free flaps. Six studies met inclusion criteria and had quantitative data suitable for meta-analysis. Intercondylar distance and gonion angle were used to assess accuracy, evaluated by mean change from preoperative VSP and postoperative imaging. The mean weighted difference in VSP intercondylar distance was 2.0 mm, compared with 3.9 mm for free hand (P = 0.101) and mean change in gonion angle for VSP was 3.6°, compared with 7.7° for free hand (P < 0.05). Efficiency assessed by mean ischemia time, was 73.8 min and 109.9 min, for VSP and free hand, respectively (P = 0.203), and by total operative time, which was 391.8 min and 457.6 min in the VSP and free hand, respectively (P = 0.340). VSP is consistently proven to be more accurate and efficient than traditional free-hand surgery; however, a standardized method for accuracy and efficiency measurements is still missing, causing heterogeneity among the scientific reports.     

Significance of clinical stage,extent of surgery and outcome in cutaneous squamous cell carcinoma of the head and neck

The authors analyzed a new clinical staging system and its correlation with pathologic findings and patient survival. Patients were eligible for inclusion in this longitudinal retrospective cohort study if they had cutaneous squamous cell carcinoma on the head or neck, underwent surgery and had a minimum 3 year follow-up. The primary study variable was using a new clinical staging system. Secondary variables included the parotid as a predictor of metastatic spread to the lymphatic nodes in the neck and primary lesion histopathologic traits. The outcome variable was patient survival. Associations between variables were assessed using Fisher's exact test, Mann–Whitney test, Kaplan–Meier method and Mantel log-rank test. p < 0.05 was considered significant. The sample comprised 103 patients. Regional metastatic disease was found in 24 patients. Histopathological analysis showed a higher frequency of neck metastatic disease if the parotid was positive for metastases (p = 0.022). An extended staging system showed significant correlation between survival rate and substages (p = 0.0105). Perineural invasion was a negative prognostic factor (p = 0.0151). The results of this study suggest that combining curative parotidectomy and elective neck dissection could be beneficial in high risk patients. Both neck and parotid metastases should be included in the clinical and histological N classification.     

Prognostic value of elective neck dissection in adenoid cystic carcinoma of head and neck: a meta-analysis: A call for randomized trials and international consensus

Adenoid cystic carcinoma of head and neck (AdCCHN) is an uncommon salivary gland cancer characterized for infrequent neck metastases, and high rate of local and distant recurrence. The aim of this meta-analysis was to analyse the significance of elective neck dissection (END) in terms of overall survival (OS) in patients with AdCCHN. A systematic literature search and meta-analysis was performed. Endpoint assessed by this meta-analysis included 5-year OS (death from any cause). Statistical heterogeneity was assessed using the Cochrane Q test and I² statistic. A pooled odds ratio (OR) was reported with 95% confidence interval (CI). There were 1934 patients in the END arm and 3083 in the observation group. The pooled OR, calculated for END vs. observation, was 0.94. Patients receiving END had similar risk for death compared to observation cohort (P = 0.76). No significant difference in final outcome after patient stratification based on T stage was identified (OR for T1/T2 1.27, P = 0.39; OR for T3/T4 0.95, P = 0.90). Observation for cN0 neck is a reasonable option in AdCCHN. These findings suggest the need for prospective trials on indications and extent of END in AdCCHN.