Injury of the external branch of the superior laryngeal nerve in thyroid surgery.

The external branch of the superior laryngeal nerve (EBSLN) innervates the cricothyroid muscle (CTM) to promote lengthening and thinning of the vocal fold, thus increasing voice pitch. The close relation with the superior thyroid vessels (STV) puts the EBSLN in risk every time the superior pole of the thyroid is dissected. It travels downward to innervate the CTM, lateral to the thyroid cartilage and to the inferior pharyngeal constrictor muscle (IPCM), being eventually covered by this muscle fibers as it approaches its entry point. During its descending course, the EBSLN curves and crosses the STV posteriorly. The lower this crossing occurs in the neck, the higher the risk of surgical damage to the nerve by transection, traction, entrapment, thermal damage or disrupted blood supply. The chances of surgical trauma are also increased by size and weight of the specimen, shorter neck length and non-white ethnicity. Voice changes following thyroid surgery are common and multifactorial. The actual rate of vocal impairment due to EBSLN injury is unclear, since changes to the everyday speaking voice can be minimal and laryngeal findings are usually subtle and controversial. CTM electroneuromyography (EMG) is the most accurate tool to diagnose abnormal EBSLN conductivity, but it is technically difficult and barely applicable in routine practice. Recommended approaches to prevent injury include: (I) individual distal ligature of the STV by the thyroid capsule; (II) visual identification of the nerve and its trajectory and (III) electrostimulation with either observation of CTM twitch or intraoperative nerve monitoring (IONM) via dedicated endotracheal tube electrodes. There is accumulating evidence that a combination of visual and standardized electrophysiological EBSLN identification with meticulous division of the STV improves preservation rates. IONM bears the additional benefits of prognostication, quantification and documentation of neural function once it allows intraoperative laryngeal EMG.

p53 and skin carcinomas with skull base invasion: a case-control study.

BACKGROUND: Some skin carcinomas may be very aggressive. Increased expression of the protein p53 has been associated with tumor aggressiveness. In this study, p53 expression was evaluated in basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) with skull base invasion, and was compared to tumors with good outcome. STUDY DESIGN AND SETTING: Expression of p53 was immunohistochemically analyzed and it was reported as present or absent in 24 BCC and 11 SCC with skull base invasion. Control group (good outcome) included 23 BCC and 10 SCC. RESULTS: Expression of p53 was noted in 70.83% of BCC with skull base invasion, compared to 43.48% in the control group (P = 0.058). Regarding SCC, p53 positivity was noted in only 9.09% of SCC with skull base invasion, compared to 40.00% in the control group (P = 0.149). CONCLUSIONS: In this study, p53 expression was more common among BCC with skull base invasion, compared to controls with good outcome, and the difference was considered marginally significant. This proportion was reversed in SCC, but the difference was not statistically significant. EBM RATING: B-3b.

Evaluation of basement membrane status in aggressive skin carcinomas with skull base invasion: a case-control study.

Some skin carcinomas may be very aggressive. Breached of basement membrane (BM) has been in some situations associated with tumor aggressiveness. In this study, the status of BM in invasion was evaluated in basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs) with skull base invasion, and it was compared with tumor's good outcome. Integrity or breached of BM was visualized using immunohistochemistry technique with anti-type IV collagen antibody. The pattern of BM was classified as intact, breached, or absent in 24 BCCs and 11 SCCs with skull base invasion. Control group (good outcome) included 23 BCCs and 10 SCCs. Breached BM and absence of BM were respectively noted in 33.33% and 45.83% of BCCs with skull base invasion, compared with 8.33% and 17.395% in the control group ( P < .001). Regarding SCCs, ruptured and absent BMs were, respectively, noted in 36.36% and 63.64% of BCCs with skull base invasion, compared with 30% and 30% in the control group ( P = .075). In this study, destruction of BM was significantly more common in BCCs with skull base invasion, in comparison with those with good outcome. In SCC, this difference was not statistically significant.

Angiogenesis and skin carcinomas with skull base invasion: a case-control study.

BACKGROUND: Some skin carcinomas may be very aggressive. Intensity of angiogenesis, measured by intratumoral vessel density using expression of CD34, has been associated with tumor aggressiveness. In this study, the expression of CD34 in basal cell carcinomas ( BCCs) and squamous cell carcinomas (SCCs) with skull base invasion was compared with that in tumors with good outcome. METHODS: Expression of CD34 was graded as mild, moderate, and intense, in 24 BCCs and 11 SCCs with skull base invasion. The control group included 23 BCCs and 10 SCCs. RESULTS: Intense expression of CD34 was noted in 25.00% of BCCs with skull base invasion, compared with 4.35% in the control group (p =.058). Regarding SCCs, intense expression of CD34 was found in 54.55% of aggressive tumors, compared with 10.00% in the control group (p =.133). CONCLUSIONS: A trend toward denser microvascular angiogenesis was observed in both BCCs and SCCs with skull base invasion compared with less aggressive controls.