Comparative Anatomic Study Between Intradural Suboccipital Retrosigmoid and Extradural Transzygomatic Middle Fossa Approaches to Expose the Trigeminal Nerve.

BACKGROUND: Meckel cave tumors are relatively rare, especially trigeminal nerve (TN) schwannomas. These tumors frequently project through the trigeminal pore, occupying the middle and posterior fossae. The most used routes to this region are the suboccipital retrosigmoid intradural approach (SORSA) and the transzygomatic middle fossa approach (TZMFA). Both approaches allow further exposure by adding intraoperative techniques, such as removing the suprameatal tubercle (retrosigmoid intradural suprameatal approach [RISA]) and the petrous apex (TZMFA-PA), respectively. This study aims to understand how TN exposure differs between both surgical approaches and how it increases by adding specific surgical maneuvers to these techniques. METHODS: Five formalin-fixed adult cadaver heads were submitted to high-resolution computed tomography and their images were loaded into the neuronavigation device. Anatomic key points were defined along the outline of the TN, and their three-dimensional spatial locations were collected following each surgical approach. This process allowed the calculation of the TN exposed area obtained through each technique. RESULTS: The mean areas of exposure of the TN were 125.9 mm2 with SORSA and 208.9 mm2 with RISA, which represents an additional mean gain of 61.92% (P = 0.047). Using TZMFA, a mean exposure of 419.24 mm2 was obtained. When TZMFA-PA was used, the mean exposed area was 486.03 mm2, representing a mean gain in the exposure area of 16.81% (P = 0.072). CONCLUSIONS: Our study suggests that TZMFA allows better exposure of TN ganglionic and postganglionic segments, and the removal of the PA adds the preganglionic segment visualization, although with less TN exposed area compared with RISA. With SORSA, the additional suprameatal tubercle removal shows the trigeminal pore and the medial margin of the central portion of the TN ganglionic segment, making it possible to expose the mouth of the Meckel cave and part of its contents.

Quality of life in adult intradural primary spinal tumors: 36-Item Short Form Health Survey correlation with McCormick and Aminoff-Logue scales.

OBJECT: The most appropriate method to determine the quality of life of patients with intradural primary spinal tumors (IPSTs) is not still well established. METHODS: Clinical data in 234 patients who underwent surgery for intradural spinal disease were collected prospectively. The 36-Item Short Form Health Survey (SF-36), a generic score scale, was administered to 148 patients with IPSTs to demonstrate if the survey can be used to effectively evaluate these patients. Forty-eight patients were excluded because they did not complete the protocol. The study was finally conducted with 100 patients (45 male and 55 female) with IPSTs, and the results were compared with those of 2 other scales: the McCormick scale and the Aminoff-Logue scale. RESULTS: Construct validity was demonstrated by confirming the hypothesized relationship between the scores of the SF-36 and the McCormick scale (p = 0.003), the Aminoff-Logue gait subscale (p = 0.025), the Aminoff-Logue micturition subscale (p = 0.013), and the Aminoff-Logue defecation subscale (p = 0.004). Reliability was demonstrated for all 8 SF-36 domain scales and the Physical Component Summary and the Mental Component Summary of the SF-36, where in each the Cronbach alpha satisfied the Nunnally criterion of > 0.85. CONCLUSIONS: The authors' results demonstrated that SF-36 provides valid and reliable data for patients with IPSTs and that the survey can be used appropriately to evaluate these patients.