Normscan: open-source Python software to create average models from CT scans.

PURPOSE: Age-matched average 3D models facilitate both surgical planning and intraoperative guidance of cranial birth defects such as craniosynostosis. We aimed to develop an algorithm that accepts any number of CT scans as input and generates highly accurate, average models with minimal user input that are ready for 3D printing and clinical use. METHODS: Using a compiled database of 'normal' pediatric computed tomography (CT) scans, we report Normscan, an open-source platform built in Python that allows users to generate normative models of CT scans through user-defined landmarks. We use the basion, nasion, and left and right porions as anatomical landmarks for initial correspondence and then register the models using the iterative closest points algorithm before downstream averaging. RESULTS: Normscan is fast and easy to use via our user interface and also creates highly accurate average models of any number of input models. Additionally, it is highly repeatable, with coefficients of variance for the surface area and volume of the average model being less than 3% across ten independent trials. Average models can then be 3D printed and/or visualized in augmented reality. CONCLUSIONS: Normscan provides an end-to-end pipeline for the creation of average models of skulls. These models can be used for the generation of databases of specific demographic anatomical models as well as for intraoperative guidance and surgical planning. While Normscan was designed for craniosynostosis repair, due to the modular nature of the algorithm, Normscan has many applications in other areas of surgical planning and research.

Alterations in Sphenoid Anatomy in Craniosynostosis: Implications for Fronto-Orbital Advancement.

OBJECTIVE: Fronto-orbital advancement involves removal of the fronto-orbital bandeau. Visualization of the saw blade is lost as it passes through the fronto-orbital-sphenoid junction (FOSJ), placing the temporal lobe at risk of injury. We aim to provide a 3D analysis of the space surrounding this osteotomy to differentiate various types of craniosynostoses. DESIGN: Retrospective cohort. SETTING: Institutional. PATIENTS: Thirty patients with isolated unicoronal synostosis, nonsyndromic bicoronal synostosis, metopic synostosis, Apert syndrome, Crouzon syndrome, and Muenke syndrome. INTERVENTIONS: CT scans conducted between 2 months to 2 years of age were 3D reconstructed to compare craniometrics against normal controls. MAIN OUTCOME MEASURE(S): Craniometrics. RESULTS: The mean bone thickness of the FOSJ at the level of the supraorbital rim was significantly small for the Apert, unicoronal and bicoronal groups. The mean vertical height of the middle cranial fossa from the lesser sphenoid wing was significantly greater in the unicoronal group. The mean vertical height of the tip of the temporal lobe from the lateral sphenoid ridge was greater in the unicoronal, isolated bicoronal, and Apert groups. The mean corneal protrusion beyond the lateral orbital rim was significantly greater in the Apert and unicoronal groups. The mean horizontal depth of the orbit was smallest in the Apert group. The mean vertical distance between the dacryon and the foramen cecum, and the mean volume of temporal lobe beneath the sphenoid shelf were the largest in the Apert group. CONCLUSIONS: Patients with Apert syndrome have the most unfavorable morphology of the anterior and middle cranial fossae.

Craniometric and Aesthetic Outcomes in Craniosynostosis Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVE: To systematically review the published comparative aesthetic outcomes, and its determinants, for craniosynostoses surgically treated by minimally-invasive cranial procedures and open cranial vault remodeling (CVR). DESIGN: PRISMA-compliant systematic review. SETTING: Not-applicable. PATIENTS/PARTICIPANTS: Articles were included if they compared spring cranioplasty, strip minimally-invasive craniectomy or CVR for outcomes related to aesthetics or head shape. Forty-two studies were included, comprising 2402 patients. INTERVENTIONS: None. MAIN OUTCOME MEASURE(S): The craniometric and PROM used to determine surgical outcomes. RESULTS: Twenty-five studies (59%) evaluated sagittal craniosynostosis, with metopic (7;17%) and unicoronal (4;10%) the next most prevalent. Thirty-eight studies (90%) included CVR, 24 (57%) included strip craniectomy with helmeting, 9 (22%) included strip craniectomy without helmeting, 11 (26%) included spring cranioplasty, and 3 (7%) included vault distraction. A majority of studies only used 1 (43%) or 2 (14%) craniometric measures to compare techniques. In sagittal synostosis, 13 (59%) studies showed no difference in craniometric outcomes, 5 (23%) showed better results with CVR, 3 (14%) with strip craniectomy, and 1 (5%) with springs. In studies describing other synostoses, 10/14 (71%) were equivocal. Subjective outcome measures followed similar trends. Meta-analysis shows no significant difference in cranial index (CI) outcomes between CVR and less invasive procedures in patients with sagittal synostosis. CONCLUSIONS: There is no difference in CI outcomes between CVR and less invasive procedures. The majority of literature comparing craniometric and aesthetic outcomes between CVR and less invasive procedures shows equivocal results for sagittal synostosis. However, the heterogeneity of data for other craniosynostoses did not allow meta-analysis.

Patient-specific Composite Anatomic Models: Improving the Foundation for Craniosynostosis Repair.

Preoperative surgical planning incorporating computer-aided design and manufacturing is increasingly being utilized today within the fields of craniomaxillofacial, orthopedic, and neurosurgery. Application of these techniques for craniosynostosis reconstruction can include patient-specific anatomic reference models, "normal" reference models or patient-specific cutting/marking guides based on the presurgical plan. The major challenge remains the lack of tangible means to transfer the preoperative plan to the operating table. We propose a simple solution to utilize a digitally designed, 3D-printed "composite model" as a structural template for cranial vault reconstruction. The composite model is generated by merging the abnormal patient cranial anatomy with the "dural surface topography" of an age-matched, sex-matched, and ethnicity-matched normative skull model. We illustrate the applicability of this approach in 2 divergent cases: 22-month-old African American male with sagittal synostosis and 5-month-old White male with metopic synostosis. The aim of this technical report is to describe our application of this computer-aided design and modeling workflow for the creation of practical 3D-printed skulls that can serve as intraoperative frameworks for the correction of craniosynostosis. With success in our first 2 cases, we believe this approach of a composite model is another step in reducing our reliance on subjective guesswork, and the fundamental aspect of the workflow has a wider application within the field of craniofacial surgery for both clinical patient care and education.

Comparison of Perineal Closure Techniques after Abdominoperineal Resections for Carcinoma of the Anus.

BACKGROUND: Perineal reconstruction following salvage APR's for squamous cell carcinoma of the anus (SCCA) are scant with conflicting results from large and single center studies. We analyzed these techniques taking into account sociodemographic and oncologic variables. METHODS: This is a retrospective cohort study from 2016-2019 using a targeted ACS/NSQIP database stratified into primary closure (PC), abdominal myocutaneous (AM), lower extremity (LE), and omental pedicled (OP) flaps. We analyzed major and wound complications through univariate and multivariate regression analysis. RESULTS: A total of 766 patients were analyzed, 512 (67%) had PC, 196 (25%) AM, 36 (5%) OP and 22 (3%) LE. Rates of chemotherapy and radiation within 90 days were similar between the groups. Having 2 or more additional organs resected was more common for the AM group (AM 4.1%, PC 1.6%, OP 3.3%, LE 0%). Overall, major complication rate was 41% (n = 324). Primary closure had 35.0%, OP 47.2%, AM 52.6%, and LE 45.5%. Wound complication rate was highest in AM with 11.7%, followed by OP 8.3%, PC 5.9%, and LE 0%. The multivariate regression analysis demonstrated none of the closure techniques to be associated with increasing or decreasing the probability of having a major or wound complication. Morbidity probability was the sole predictor of major complication (OR 1.07, 95% CI 1.04-1.1). CONCLUSIONS: Myocutaneous and omental flaps are associated with comparable wound and major complications when taking into account the baseline, oncologic and perioperative variables that drive the clinical decision making when selecting a perineal reconstruction.

Outcomes of perineal wound closure techniques after abdominoperineal resections in rectal cancer: an NSQIP propensity score matched study.

Perineal defects following abdominoperineal resections (APRs) for rectal cancer may require myocutaneous or omental flaps depending upon anatomic, clinical and oncologic variables. However, studies comparing their efficacy have shown contradictory results. We aim to compare postoperative complication rates of APR closure techniques in rectal cancer using propensity score-matching. The American College of Surgeons Proctectomy Targeted Data File was queried from 2016 to 2019. The study population was defined using CPT and ICD-10 codes for patients with rectal cancer undergoing APR, stratified by repair technique. Perioperative demographic and oncologic variables were controlled for by propensity-score matching. Multivariate logistic regression analysis was performed for wound and major complications (MCs). Of the 3291 patients included in the study, 85% underwent primary closure (PC), 8.3% rectus abdominis myocutaneous (RAM) flap, 4.9% pedicled omental flap with PC, and 1.9% lower extremity (LE) flap repair. Primary closure rates were significantly higher for patients with stage T1 and T2 tumors (p < 0.001). RAM and LE flaps were most used with multi-organ resections, 24% and 25%, respectively (p < 0.001). Similarly, cases with T4 tumors used these flaps more frequently, 30% and 40%, respectively (p < 0.001). After propensity score matching for comorbidities and oncologic variables, there was no significant difference in 30-day postoperative wound or MC rates between perineal closure techniques. The complication rates of the different closure techniques are comparable when tumor stage is considered. Therefore, tumor staging and concurrent procedures should guide clinical decision making regarding the appropriate use of each technique.

Primary Cleft Rhinoplasty: A Systematic Review of Results, Growth Restriction, and Avoiding Secondary Rhinoplasty.

BACKGROUND: Primary rhinoplasty during correction of unilateral cleft lip continues to be a topic of debate because of concerns that early nasal intervention may affect nasal and maxillary development over the long term. This study aims to determine the volume and quality of evidence for and against primary unilateral cleft rhinoplasty. METHODS: A systematic review was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were pulled from PubMed and EMBASE and screened by title and abstract. Studies with human participants undergoing rhinoplasty at the time of unilateral cleft lip repair and some evaluation of the nasal outcome were included. Studies with a large proportion of syndromic patients, case reports, editorials, letters, reviews, studies exclusive to bilateral clefts, and studies not available in English were excluded. Those that met criteria were then systematically reviewed. RESULTS: Twenty-five articles were included. Ten articles that assessed the results of primary rhinoplasty subjectively all supported cleft lip repair with primary rhinoplasty. Sixteen articles assessed the results of primary rhinoplasty objectively, with 15 supporting primary rhinoplasty during cleft lip repair. Eight of nine studies that evaluated nasal growth and development over time found no restriction in nasal development. Five studies with a follow-up period of at least 6 years found that the percentage of patients who avoided revision rhinoplasty ranged from 43% to 100%. There were significant risks of bias in the majority of studies. CONCLUSION: The majority of studies reviewed support that primary rhinoplasty during unilateral cleft lip repair results in good outcomes with limited or no effect on nasal growth.

A Novel Method of Fibula Flap In Situ Distraction Osteogenesis Prior to Flap Transfer.

BACKGROUND: The fibula flap is the workhorse for mandibular reconstruction, but fibula bone width is not ideal to match mandibular height. In this study, in situ widening of the fibula with distraction osteogenesis before transfer is evaluated as a solution. The authors present a proof of concept of this technique with a patient series, including one patient who has undergone subsequent orthognathic surgery of the reconstructed mandible. METHODS: A retrospective review of patients undergoing the authors' technique was performed. A longitudinal fibula osteotomy was made in situ and distraction was performed in the leg to widen the fibula. After distraction and consolidation periods, flaps were osteotomized and transferred to the mandible. RESULTS: This technique was applied to three patients (ages 9, 11, and 13 years) with Pruzansky III mandibular hypoplasia at the authors' institution over 15 years. In all cases, bony union was achieved. Mean surgical follow-up was 5 years. No significant morbidity occurred at the donor sites. Partial flap resorption was observed a number of years postoperatively in one patient. Temporomandibular joint ankylosis developed in one patient after closed treatment of an unrelated mandible fracture. A sinus tract developed in one patient, requiring débridement of a partial flap necrosis. One patient had orthognathic surgery, including osteotomy of the fibula. CONCLUSIONS: In situ fibula distraction osteogenesis is a novel technique to prelaminate a fibula flap before transfer to the mandible. This method allows for the reconstruction of challenging mandibular defects without compromising bone height, pedicle length, or the ability to perform orthognathic surgery. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Use of a Waterproof Camera Immersed in Povidone-Iodine to Improve Intraoperative Photography.

Intraoperative photography has the potential to raise costs and introduce possible contamination but is essential for documentation in plastic surgery. The authors evaluate their use of a waterproof camera immersed in povidone-iodine for taking intraoperative photographs in an efficient manner. A waterproof camera is immersed in povidone-iodine during surgery and photographs are taken as needed by the operating surgeon or assistant without a change of gloves. A retrospective chart review was performed, evaluating serious infections and the number of photographs taken per procedure in the years before and after the camera was used. Bacterial cultures were taken of three areas of the camera on 10 consecutive operating days and evaluated for growth. The number of serious infections did not change after the camera protocol was implemented. The mean number of photographs taken per case increased significantly with the use of this camera. All cultures of the camera were negative. The use of a waterproof camera immersed in povidone-iodine allows efficient and improved intraoperative photographic documentation by the surgeon. It does not appear to increase the risk of infection or introduce contamination.

Long-term Outcomes After Pediatric Free Flap Reconstruction.

INTRODUCTION: Whereas free tissue transfer has evolved to minimize morbidity in adults, less is known about outcomes after free flaps in children. This study sought to assess short- and long-term outcomes after microvascular reconstruction in the pediatric population. METHODS: Short- and long-term outcomes of free tissue transfer were assessed using chart-review and quality-of-life surveys. The Pediatric Outcomes Data Collection Instrument was used to evaluate overall health, pain, and ability to participate in normal daily and more vigorous activities. Patient or parent responses were compared against normative data. RESULTS: Forty-two patients underwent 48 flap reconstructions at a mean age of 8 years. Median follow-up was 14.9 years. Indications included congenital nevi (n = 19, 42%), lymphatic/vascular malformations (n = 8, 19%), and trauma/burns (n = 6, 14%). There were 21 fasciocutaneous (44%), 19 muscle/myocutaneous (40%), 6 fascial/peritoneal (13%), and 2 osteocutaneous flaps (4%). Major flap complications were observed in 4 patients (9%), whereas major donor-site complications occurred in 2% (1 patient). Valid contact information was available for 25 patients; 16 of these completed surveys (64%). Pediatric Outcomes Data Collection Instrument scores for mobility (median, 52), sports/physical functioning (median, 56), happiness (median, 50), and pain/comfort (median, 56) were not significantly different from normative population score of 50. Similarly, median global functioning score was 99 (maximum, 100) and did not differ between flap types. DISCUSSION: Free tissue transfer in the pediatric population is reliable and well-tolerated over time. Surgeons should not hesitate to use free flaps when clinically indicated for pediatric patients.

Superficial Inferior Epigastric Artery Flap for a Total Parotidectomy Defect.

Introduction: The superficial inferior epigastric artery flap offers ample volume for reconstruction, an inconspicuous scar, and no functional donor site deficit. This report details its use for volume replacement after parotidectomy. Methods: We report a 27-year-old woman with recurrent acinic cell carcinoma, requiring left total parotidectomy and partial mastoidectomy. In anticipation of significant contour deficit and postoperative radiation, reconstruction with a superficial inferior epigastric artery adipose-free flap was performed. Results: Resection and reconstruction were carried out with no complications. The postoperative course was uneventful, with recovery of facial nerve function and an aesthetic, symmetrical outcome. The donor site scar is completely hidden by underwear. Conclusion: The superficial inferior epigastric artery flap represents an underused option in head and neck reconstruction. It offers similar benefits to that of the parascapular flap but with the advantages of a 2-team approach and a less conspicuous donor scar.

TUGs into VUGs and Friendly BUGs: Transforming the Gracilis Territory into the Best Secondary Breast Reconstructive Option.

BACKGROUND: The best secondary option for autologous breast reconstruction remains controversial. Limitations of the gracilis myocutaneous flap, including volume, skin paddle reliability, and donor morbidity, have been addressed by several modifications, hereby expanding its role in the decision tree for autologous breast reconstruction. This report documents the authors' experience with gracilis flap breast reconstruction. METHODS: This is a retrospective case series of a prospectively maintained database of patients undergoing breast reconstruction with the free gracilis myocutaneous flap, including the transverse upper gracilis, vertical upper gracilis, and bilateral stacked vertical upper gracilis. RESULTS: Twenty-two patients received gracilis myocutaneous flaps. Fourteen (63.6 percent) had previous attempted breast reconstructions. Indications for gracilis donor site were previous abdominoplasty/abdominal flap (n = 15, 68 percent), insufficient abdominal tissue (n = 6, 27 percent), and patient preference (n = 1, 5 percent). Six patients underwent bilateral reconstruction, and five underwent unilateral reconstruction with bilateral stacked gracilis flaps. The skin paddle was transverse in four flaps (12 percent) and vertical in 29 (88 percent). There was one flap loss (3 percent); there were two occurrences of fat necrosis (6 percent). There were two minor donor site dehiscences (6 percent), one infection (3 percent), and one seroma (3 percent). CONCLUSIONS: The free gracilis flap is a versatile option for patients undergoing breast reconstruction, particularly when the abdominal donor site is unavailable. The vertical pattern is the authors' preferred technique, as it avoids some of the problems associated with transverse patterns. Stacked flaps further expand the utility of this technique, which the authors regard as the best secondary option for autologous breast reconstruction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Exchange hybrid cranioplasty using particulate bone graft and demineralized bone matrix: the best of both worlds.

Reconstruction of craniofacial defects in children presents several challenges that are not encountered in the adult population. Autologous bone grafts have long been the criterion standard for repairing these defects. Recently, several new materials and techniques have expanded our arsenal of reconstructive options. In this clinical report, we describe the use of both particulate bone grafting and demineralized bone matrix together to repair craniofacial defects encountered in pediatric patients.

Implications of a positive sentinel node in oral squamous cell carcinoma.

BACKGROUND: The role of sentinel node biopsy in head and neck cancer is currently being explored. Patients with positive sentinel nodes were investigated to establish if additional metastases were present in the neck, their distribution, and their impact on outcome. METHODS: In all, 109 patients (n = 109) from 15 European centers, with cT1/2,N0 tumors, and a positive sentinel lymph node were identified. Kaplan-Meier and univariate and multivariate logistic regression analysis were used to identify variables that predicted for additional positive nodes and their position within the neck. RESULTS: A total of 122 neck dissections were performed in 109 patients. Additional positive nodes were found in 34.4% of cases (42/122: 18 same, 21 adjacent, and 3 nonadjacent neck level). Additional nodes, especially if outside the sentinel node basin, had an impact on outcome. CONCLUSIONS: The results are preliminary but suggest that both the number and the position of positive sentinel nodes may identify different prognostic groups that may allow further tailoring of management plans.

Sentinel node biopsy in head and neck squamous cell cancer: 5-year follow-up of a European multicenter trial.

BACKGROUND: Sentinel node biopsy (SNB) may represent an alternative to elective neck dissection for the staging of patients with early head and neck squamous cell carcinoma (HNSCC). To date, the technique has been successfully described in a number of small single-institution studies. This report describes the long-term follow-up of a large European multicenter trial evaluating the accuracy of the technique. METHODS: A total of 227 SNB procedures were carried out across 6 centers, of which 134 were performed in clinically T1/2 N0 patients. All patients underwent SNB with preoperative lymphoscintigraphy, intraoperative blue dye, and handheld gamma probe. Sentinel nodes were evaluated with hematoxylin and eosin (H&E) staining, step-serial sectioning (SSS), and immunohistochemistry (IHC). There were 79 patients who underwent SNB as the sole staging tool, while 55 patients underwent SNB-assisted elective neck dissection. RESULTS: Sentinel nodes were successfully identified in 125 of 134 patients (93%), with a lower success rate observed for floor-of-mouth tumors (FoM; 88% vs. 96%, P = 0.138). Also, 42 patients were upstaged (34%); of these, 10 patients harbored only micrometastatic disease. At a minimum follow-up of 5 years, the overall sensitivity of SNB was 91%. The sensitivity and negative predictive values (NPV) were lower for patients with FoM tumors compared with other sites (80% vs. 97% and 88% vs. 98%, respectively, P = 0.034). CONCLUSIONS: Sentinel node biopsy is a reliable and reproducible means of staging the clinically N0 neck for patients with cT1/T2 HNSCC. It can be used as the sole staging tool for the majority of these patients, but cannot currently be recommended for patients with tumors in the floor of the mouth.

Single-stage reconstruction of a devastating antebrachial injury with brachial artery, median nerve, and soft tissue deficit: a case report and review of the literature.

OBJECTIVE: We present a case of a 31-year-old man who fell through a skylight sustaining a deep laceration injury to his dominant arm. A single-stage radial artery flow-through free flap and cabled sural nerve graft for reconstruction of a complex antebrachial defect involving skin, soft tissue, muscle, brachial artery, and median nerve was performed. A technical description of the case and review of the literature are described. METHODS: Traumatic injuries to the arm and antecubital fossa often lead to devastating outcomes. Advances in microsurgical technique as well as improved skin and dermal substitutes have allowed improved outcomes as well as shorter hospital stays. In this case, surgical treatment involved microsurgical reconstruction of the brachial artery with a radial artery flow-through flap and a single-stage donor-site closure with an Integra dermal matrix template and split-thickness skin graft. RESULTS: Successful vascular flow and soft tissue coverage were performed with successful salvage of the limb. CONCLUSION: A single-stage reconstruction versus a multistage, delayed reconstruction of a devastating arm injury with a radial forearm flow-through flap and single-stage closure with Integra and autologous skin graft can provide a safe, effective, and clinically satisfactory outcome.

Joint practice guidelines for radionuclide lymphoscintigraphy for sentinel node localization in oral/oropharyngeal squamous cell carcinoma.

Involvement of the cervical lymph nodes is the most important prognostic factor for patients with oral/oropharyngeal squamous cell carcinoma (OSCC), and the decision whether to electively treat patients with clinically negative necks remains a controversial topic. Sentinel node biopsy (SNB) provides a minimally invasive method of determining the disease status of the cervical node basin, without the need for a formal neck dissection. This technique potentially improves the accuracy of histological nodal staging and avoids over-treating three-quarters of this patient population, minimizing associated morbidity. The technique has been validated for patients with OSCC, and larger-scale studies are in progress to determine its exact role in the management of this patient population. This article was designed to outline the current best practice guidelines for the provision of SNB in patients with early-stage OSCC, and to provide a framework for the currently evolving recommendations for its use. These guidelines were prepared by a multidisciplinary surgical/nuclear medicine/pathology expert panel under the joint auspices of the European Association of Nuclear Medicine (EANM) Oncology Committee and the Sentinel European Node Trial Committee.

Sentinel node biopsy for early oral and oropharyngeal squamous cell carcinoma.

The appearance of lymph node metastases represents the most important adverse prognostic factor in head and neck squamous cell carcinoma. Therefore, accurate staging of the cervical nodes is crucial in these patients. The management of the clinically and radiologically negative neck in patients with early oral and oropharyngeal squamous cell carcinoma is still controversial, though most centers favor elective neck dissection for staging of the neck and removal of occult disease. As only approximately 30% of patients harbor occult disease in the neck, most of the patients have to undergo elective neck dissection with no benefit. The sentinel node biopsy concept has been adopted from the treatment of melanoma and breast cancer to early oral and oropharyngeal squamous cell carcinoma during the last decade with great success. Multiple validation studies in the context of elective neck dissections revealed sentinel node detection rates above 95% and negative predictive values for negative sentinel nodes of 95%. Sentinel node biopsy has proven its ability to select patients with occult lymphatic disease for elective neck dissection, and to spare the costs and morbidity to patients with negative necks. Many centers meanwhile have abandoned routine elective neck dissection and entered in observational trials. These trials so far were able to confirm the high accuracy of the validation trials with less than 5% of the patients with negative sentinel nodes developing lymph node metastases during observation. In conclusion, sentinel node biopsy for early oral and oropharyngeal squamous cell carcinoma can be considered as safe and accurate, with success rates in controlling the neck comparable to elective neck dissection. This concept has the potential to become the new standard of care in the near future.

Sentinel node biopsy in floor of mouth cancers: the need to clear level I.

Tumour lymphatic spread in head and neck squamous cell carcinomas is the single most important prognostic indicator. With advances in histological examination, sentinel node biopsy is proving to be an accurate method for staging the clinically N0 neck. We have previously highlighted the difficulties in locating sentinel nodes in the neck from floor of mouth primaries. We also raised the question whether level I nodes should be cleared as part of sentinel node procedures in floor of mouth tumours. We describe a case which illustrates the difficulties encountered when performing sentinel node biopsies in patients with floor of mouth cancers and the rationale behind asking such a question.

Predictive factors for failure to identify sentinel nodes in head and neck squamous cell carcinoma.

BACKGROUND: The aim of this study was to ascertain which factors determine success of sentinel node biopsy (SNB). METHODS: We conducted a retrospective review of 121 patients with head and neck squamous cell carcinoma undergoing SNB to stage the neck. All patients underwent the triple-diagnostic procedure of preoperative lymphoscintigraphy, intraoperative blue dye, and a gamma probe. Factors contributing to failure of SNB were identified. RESULTS: SNB was unsuccessful in 12 of 121 patients (10%). Seven of the 12 patients had cT1/cT2 tumors, and 6 of these were located in the floor of mouth. SN identification was more likely to be successful in patients with cN0 necks, but this did not reach statistical significance (92% vs 84%, p = .268). Factors associated with failure included T classification (p = .01), tumor site (p = .05), and negative preoperative lymphoscintigraphy (p = .0174). CONCLUSION: Successful sentinel lymph node harvest is related to primary tumor site, T classification, and the presence of nodes on preoperative lymphoscintigraphy.