Mihir R. Patel

Endoscopic pedicled nasoseptal flap reconstruction for pediatric skull base defects

A prospective study of endoscopic expanded endonasal approaches (EEA) with nasoseptal flap reconstructions revealed anecdotal evidence of less available relative septal length in pediatric patients. Our goal is to use radioanatomic analysis of computed tomography (CT) scans to determine limitations of the nasoseptal flap in pediatric skull base reconstruction and to describe clinical outcomes after using the nasoseptal flap in six pediatric patients.

How to Choose? Endoscopic Skull Base Reconstructive Options and Limitations

As endoscopic skull base resections have advanced, appropriate reconstruction has become paramount. The reconstructive options for the skull base include both avascular and vascular grafts. We review these and provide an algorithm for endoscopic skull base reconstruction. One hundred and sixty-six skull base dural defects, reconstructed with an endonasal vascular flap, were examined. As an adjunct, avascular reconstruction techniques are discussed to illustrate all options for endonasal skull base reconstruction. Cerebrospinal fluid (CSF) leak rates are also discussed. Small CSF leaks may be successfully repaired with various avascular grafting techniques. Endoscopic endonasal approaches (EEAs) to the skull base often have larger dural defects with high-flow CSF leaks. Success rates for some EEA procedures utilizing avascular grafts approach 90%, yet in high-flow leak situations, success rates are much lower (50 to 70%). Defect location and complexity guides vascularized flap choice. When nasoseptal flaps are unavailable, anterior/sellar defects are best managed with an endoscopically harvested pericranial flap, whereas clival/posterior defects may be reconstructed with an inferior turbinate or temporoparietal flap. An endonasal skull base reconstruction algorithm was constructed and points to increased use of various vascularized reconstructions for more complex skull base defects.

Oral and plunging ranulas: What is the most effective treatment?

Preferred treatment of oral/plunging ranulas remains controversial. We present our experience with ranulas at the University of North Carolina (UNC) and review the literature.

Pericranial flap for endoscopic anterior skull-base reconstruction: Clinical outcomes and radioanatomic analysis of preoperative planning

BACKGROUNDOne of the major challenges of cranial base surgery is reconstruction of the dural defect and prevention of postoperative cerebrospinal fluid (CSF) fistula. The introduction of endoscopic techniques and an endonasal approach to the ventral skull base has created new challenges for reconstruction. OBJECTIVEWe have developed an endoscopic pericranial flap (PCF) for skull base reconstruction and hereby present the initial cohort of patients who had endonasal reconstruction with a PCF after endoscopic skull base resection. We also demonstrate a method to radiographically incorporate anticipated skull base defects for preoperative planning of PCF length. METHODSDural defects after endonasal skull base resection of invasive tumors were reconstructed with an onlay PCF (n = 10). We performed radiological studies to assist preoperative planning for where to make incisions while harvesting a PCF for anterior skull base, sellar, and clival defects. RESULTSEach of the 10 patients had excellent healing of their skull base and had no evidence of any postoperative cerebrospinal fluid leaks. Eight patients had radiation therapy without flap complications. Radiographic studies demonstrate that the adequate PCF length, covering defects of the anterior skull base, sellar, and clival defects are 11.31 to 12.44 cm, 14.31 to 15.57 cm, and 18.5 to 20.42 cm, respectively. CONCLUSIONThe PCF provides an option for endonasal reconstruction of cranial base defects and can be harvested endoscopically. Pre-operative radiographic evaluation may guide surgical planning. There is minimal donor site morbidity, and the flap provides enough surface area to cover the entire ventral skull base.

Beyond the nasoseptal flap: Outcomes and pearls with secondary flaps in endoscopic endonasal skull base reconstruction

Endoscopic endonasal skull base surgery defects require effective reconstruction. Although the nasoseptal flap (NSF) has become our institutions workhorse for large skull base defects with cerebrospinal fluid (CSF) leaks, situations where it is unavailable require secondary flaps. Clinical outcomes, pearls and pitfalls, and an algorithm will be presented for these secondary flaps.

Immunohistochemical Distinction of Follicular Thyroid Adenomas and Follicular Carcinomas

OBJECTIVES To use immunohistochemical (IHC) evaluation of proteins encoded by genes that were differentially expressed in follicular thyroid adenomas (FAs) vs follicular thyroid carcinomas (FTCs) to distinguish benign vs malignant follicular thyroid lesions. Multiple gene microarray studies suggest that benign and malignant follicular thyroid neoplasms have different gene expression profiles. DESIGN Immunohistochemical analysis of thyroid neoplasms, including FA (n = 62), FTC (n = 62), and follicular variant of papillary thyroid carcinoma (n = 58), using tissue microarrays. We evaluated antibodies galectin-3, autotaxin, intestinal trefoil factor 3 (TFF3), extracellular matrix metalloproteinase inducer (EMMPRIN), and growth arrest and DNA damage-inducible protein 153 (GADD153). We analyzed data for quantitative differences in IHC intensity and the percentage of positive cells between FAs and combined follicular carcinomas. Sensitivity and specificity analysis are reported, along with a dual-protein clinical algorithm. SETTING Academic tertiary care center. PATIENTS Adults with known follicular and papillary thyroid lesions that were surgically resected during the past 15 years. MAIN OUTCOME MEASURES Sensitivity and specificity of individual and combined antibodies for detecting benign from malignant lesions. RESULTS Quantitative analysis showed IHC validation of the gene expression differences noted in previously published microarray reports. A significantly higher percentage of FTC cells stained with galectin-3, EMMPRIN, and GADD153. Galectin-3 and EMMPRIN also showed a significantly higher intensity of staining in FTC cells. Compared with malignant lesions, TFF3 stained a greater cell percentage in FAs. Galectin-3 (sensitivity, 0.72; specificity, 0.62) and EMMPRIN (sensitivity, 0.63; specificity, 0.49) had the most promising diagnostic potential with a dual-protein sensitivity of 0.80 and specificity of 0.70. Autotaxin and GADD153 had overall higher sensitivities (0.88 and 0.82, respectively) but very poor specificities (0.02 and 0.21, respectively). CONCLUSIONS Protein expression data validate the pooled gene expression results that differentiate FTC from FA. Our results show promise for multiple-protein IHC analysis algorithms and their diagnostic ability. Future studies should focus on clinical translation of these molecular differences for the diagnosis of follicular thyroid neoplasms.

Anatomical considerations for endoscopic endonasal skull base surgery in pediatric patients

Pediatric skull base surgery is limited by several boney sinonasal landmarks that must be overcome prior to tumor dissection. When approaching a sellar or parasellar tumor, the piriform aperture, sphenoid sinus pneumatization, and intercarotid distances are areas of potential limitation. Quantitative pediatric anatomical measurements relevant to skull base approaches are lacking. Our goal was to use radio‐anatomic analysis of computed tomography scans to determine anatomical limitations for trans‐sphenoidal approaches in pediatric skull base surgery.

Molecular Biology of Head and Neck Cancer: Risks and Pathways

Patients present with a differential baseline risk of cancer based on normal and expected variations in genes associated with cancer. The baseline risk of developing cancer is acted on throughout life as the genome of different cells interacts with the environment in the form of exposures (eg, toxins, infections). As genetic damage is incurred throughout a lifetime (directly to DNA sequences or to the epigenome), events are set in motion to progressively disrupt normal cellular pathways toward tumorigenesis. This article attempts to characterize broad categories of genetic aberrations and pathways in a manner that might be useful for the clinician to understand the risk of developing cancer, the pathways that are disrupted, and the potential for molecular-based diagnostics.

A controlled laboratory and clinical evaluation of a three-dimensional endoscope for endonasal sinus and skull base surgery.

Background One criticism of current video systems for endoscopic surgery is that two-dimensional (2D) images lack depth perception and may impair surgical dissection. To objectively measure the efficacy of 3D endoscopy, we designed a training model with specific tasks to show potential differences between 2D and 3D endoscopy. Its clinical value was then evaluated during endoscopic sinus and skull base surgical cases. Methods Fifteen subjects were grouped according to endoscopic experience: novices and nonnovices. A training model was constructed to include five tasks: incision manipulation; ring transfer; nerve hook; distance estimation, visual only; and distance estimation, visual and tactile. Each participant was assessed with both a standard 2D endoscope and a 3D endoscope. The clinical value of a 3D endoscope (Visionsense, Ltd., Petach Tikva, Israel) was then examined in four endoscopic sinus cases and four skull base cases. Results Of the subjects, six (40%) were novices. Overall, the errors committed during any one task were not significantly different between systems. Novices trended toward more success during the nerve hook task using the 3D system. With size cueing versus visualization alone, distance estimation was significantly more accurate. Novices tended to prefer the 3D system and experienced surgeons disliked the initial learning curve. Advantages were particularly noticed during skull base surgery; subjectively improved depth perception was beneficial during vascular dissection. Conclusion Three-dimensional endoscopy may improve depth perception and performance for novices. The 3D endoscope is a safe and feasible tool for endoscopic sinus and skull base surgery; it is promising for improving microneurosurgical dissection precision transnasally.

High XRCC1 Protein Expression Is Associated with Poorer Survival in Patients with Head and Neck Squamous Cell Carcinoma

Purpose: We evaluated X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1) protein in head and neck squamous cell carcinoma (HNSCC) patients in association with outcome. Experimental Design: XRCC1 protein expression was assessed by immunohistochemical (IHC) staining of pretreatment tissue samples in 138 consecutive HNSCC patients treated with surgery (n = 31), radiation (15), surgery and radiation (23), surgery and adjuvant chemoradiation (17), primary chemoradiation (51), and palliative measures (1). Results: Patients with high XRCC1 expression by IHC (n = 77) compared with patients with low XRCC1 expression (n = 60) had poorer median overall survival (OS; 41.0 months vs. OS not reached, P = 0.009) and poorer progression-free survival (28.0 months vs. 73.0 months, P = 0.031). This association was primarily due to patients who received chemoradiation (median OS of high- and low-XRCC1 expression patients, 35.5 months and not reached respectively, HR 3.48; 95% CI: 1.44–8.38; P = 0.006). In patients treated with nonchemoradiation modalities, there was no survival difference by XRCC1 expression. In multivariable analysis, high XRCC1 expression and p16INK4a-positive status were independently associated with survival in the overall study population (HR = 2.62; 95% CI: 1.52–4.52; P < 0.001 and HR = 0.21; 95% CI: 0.06–0.71; P = 0.012, respectively) and among chemoradiation patients (HR = 6.02; 95% CI: 2.36–15.37; P < 0.001 and HR = 0.26; 95% CI: 0.08–0.92, respectively; P = 0.037). Conclusions: In HNSCC, high XRCC1 protein expression is associated with poorer survival, particularly in patients receiving chemoradiation. Future validation of these findings may enable identification of HNSCC expressing patients who benefit from chemoradiation treatment. Clin Cancer Res; 17(20); 6542–52. ©2011 AACR.