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Nefopam is a non-opioid, centrally acting, non-steroidal analgesic drug. It is used to treat mild to moderate painful conditions. Although developed about five decades ago, its use has gained resurgence in recent years. This study was designed to investigate the effects of different analgesic doses of nefopam on the liver and kidneys of mice. Forty albino mice were divided into four groups of 10 mice for each group. Group 1, 2 &3 received a daily intraperitoneal injection of Nefopam at 10, 20, and 30 mg/kg doses, respectively. The fourth group (control group) received injections of normal saline. After two weeks of treatment, the animals were weighed and sacrificed, and then blood was collected for liver enzymes analysis and renal function test as well as histological assessment. The results revealed that the bodyweight increase ratio was significantly lower in group 3 (P-value <0.01). All tested liver enzymes i.e., ALT, AST, and ALP levels showed a highly significant (P-value <0.01) change among the tested groups. Although ALT remained within normal limits in the first two groups and normal group, in group 3 (30 mg/kg), its level exceeded the normal value. Liver enzyme changes reflected and supported the histopathological findings in the liver tissue. Group 2 & 3 showed varying degrees of hepatotoxicity, ranging from granulomatous lymphocytic infiltration to micro-vesicular steatosis and apoptotic pictures. Both kidney function test and histopathological examination, on the other hand, illustrated insignificant effect (P-value >0.05) of Nefopam on the kidneys. Nefopam is well tolerable by the liver at low analgesic doses but may have detrimental effects at higher analgesic doses and prolonged duration of intake.

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BACKGROUND AND OBJECTIVES: Access to the anterolateral pontine lesions can be achieved through the peritrigeminal and supratrigeminal safe entry zones using Kawase, retrosigmoid, or translabyrinthine approaches. However, these approaches entail shallow extensive dissection, tangential access, and compromise vestibulocochlear function. We aimed to investigate infratentorial presigmoid retrolabyrinthine approach to access pontine lesions through the peritrigeminal zone. METHODS: We performed 10 presigmoid retrolabyrinthine suprameatal approach dissections in 5 cadaveric heads. Anatomic-radiological characteristics and variations were evaluated. Six morphometric parameters were measured and analyzed to predict surgical accessibility. RESULTS: The pontine infratrigeminal area was accessible in all patients. The mean exposed area of the anterolateral pontine surface was 98.95 cm2 (±38.11 cm2). The mean length of the exposed trigeminal nerve was 7.9 cm (±2.9 cm). Preoperative anatomic-radiological parameters may allow to select patients with favorable anatomy that offers appropriate surgical accessibility to the anterior pontine cavernoma through a presigmoid retrolabyrinthine corridor. CONCLUSION: Anterolateral pontine lesions can be accessed through a minimally invasive infratentorial presigmoid retrolabyrinthine approach by targeting the infratrigeminal safe entry zone. Further clinical studies should be conducted to evaluate the viability of this technique for treating these complex pathologies in real clinical settings.

OBJECTIVE The "presigmoid corridor" covers a spectrum of approaches using the petrous temporal bone either as a target in treating intracanalicular lesions or as a route to access the internal auditory canal (IAC), jugular foramen, or brainstem. Complex presigmoid approaches have been continuously developed and refined over the years, leading to great heterogeneity in their definitions and descriptions. Owing to the common use of the presigmoid corridor in lateral skull base surgery, a simple anatomy-based and self-explanatory classification is needed to delineate the operative perspective of the different variants of the presigmoid route. Herein, the authors conducted a scoping review of the literature with the aim of proposing a classification system for presigmoid approaches. METHODS The PubMed, EMBASE, Scopus, and Web of Science databases were searched from inception to December 9, 2022, following the PRISMA Extension for Scoping Reviews guidelines to include clinical studies reporting the use of "stand-alone" presigmoid approaches. Findings were summarized based on the anatomical corridor, trajectory, and target lesions to classify the different variants of the presigmoid approach. RESULTS Ninety-nine clinical studies were included for analysis, and the most common target lesions were vestibular schwannomas (60/99, 60.6%) and petroclival meningiomas (12/99, 12.1%). All approaches had a common entry pathway (i.e., mastoidectomy) but were differentiated into two main categories based on their relationship to the labyrinth: translabyrinthine or anterior corridor (80/99, 80.8%) and retrolabyrinthine or posterior corridor (20/99, 20.2%). The anterior corridor comprised 5 variations based on the extent of bone resection: 1) partial translabyrinthine (5/99, 5.1%), 2) transcrusal (2/99, 2.0%), 3) translabyrinthine proper (61/99, 61.6%), 4) transotic (5/99, 5.1%), and 5) transcochlear (17/99, 17.2%). The posterior corridor consisted of 4 variations based on the target area and trajectory in relation to the IAC: 6) retrolabyrinthine inframeatal (6/99, 6.1%), 7) retrolabyrinthine transmeatal (19/99, 19.2%), 8) retrolabyrinthine suprameatal (1/99, 1.0%), and 9) retrolabyrinthine trans-Trautman’s triangle (2/99, 2.0%). CONCLUSIONS Presigmoid approaches are becoming increasingly complex with the expansion of minimally invasive techniques. Descriptions of these approaches using the existing nomenclature can be imprecise or confusing. Therefore, the authors propose a comprehensive classification based on the operative anatomy that unequivocally describes presigmoid approaches simply, precisely, and efficiently.