PubMed · 10636310
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P J Baskett, P A Steen. 1999. Interventions on the recently dead.. https://doi.org/10.1016/s0300-9572(99)00108-2
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The infratemporal fossa (ITF) is a deep retromaxillary space corresponding to the inferior aspect of the middle cranial fossa. There are numerous surgical approaches, indicating the difficulty of access, accentuated by the communications with the neighboring regions. The aim of this anatomical study was the optimization and photographic demonstration of the pre-auricular infra-temporal trans-zygomatic approach combined with a trans-mandibular approach allowing access to the different regions of the ITF. Six human heads preserved in formalin were dissected under the operating microscope (magnification between x6 and x4). Intra-arterial injection of colored silicone had been done in advance. A plastinated hemi-head was conserved as a teaching and training specimen using the S10 silicone technique. After a pre-auricular temporo-cervical incision, skin flaps, the superficial temporalis fascia and the temporal fascia were elevated. The facial nerve and its branches were preserved and the temporal and zygomatic branches were protected by the superficial temporalis fascia. The division of the temporal muscle and osteotomy of the zygomatic arch opened the superior part of the ITF. Osteotomy of the mandibular ramus preserving the division of the mandibular nerve opened the inferior part of the ITF. This was thus perfectly exposed and access was not impeded by the trunk of the facial nerve and its branches. The place of this complex approach is discussed among the principal exocranial surgical approaches to the ITF.
STUDY DESIGN: Human cadaveric lumbar spines were used to assess the temperature and thermal dose distribution during intradiscal electrothermal therapy in vitro. OBJECTIVES: To determine whether intradiscal electrothermal therapy produces adequate tissue temperatures to denature annular collagen or ablate nerve cells. SUMMARY OF BACKGROUND DATA: Several hypothesized mechanisms for the effect of intradiscal electrothermal therapy have been suggested and include: 1) shrinkage of the nucleus and/or the annulus fibrosus by contraction of collagen fibers; and 2) thermal ablation of sensitive nerve fibers in the outer annulus. METHODS: Intradiscal electrothermal therapy was performed using the standard clinical protocol on 12 lumbar specimens in a 37.0 degrees C water bath using the SpineCath by Oratec. Temperatures were recorded simultaneously at 40 different locations in the disc. Thermal dose (Equivalent Minutes 43.0 degrees C) was calculated at each temperature point. RESULTS: The highest temperature measured (out of 520 points) was 64.0 degrees C and was within 1 mm of the heating coil. Temperatures in excess of 60 degrees C were all within 1 to 2 mm of the intradiscal electrothermal therapy catheter surface, the 50 to 60 degrees C range extended approximately 6 mm, above 48 degrees C extended approximately 7 mm, and above 45 degrees C extended to approximately 10 mm. Less than 2% of points achieved temperatures sufficient for collagen denaturation (>60 degrees C). On average, 42.5% of points accumulated >250 Equivalent Minutes 43.0 degrees C, a conservative common dose threshold for thermal necrosis of cells. The time history of thermal measurements demonstrated that the disc temperature had not reached steady state by the end of the heating protocol (16.5 minutes). CONCLUSIONS: Except for a very limited margin (1-2 mm) around the catheter, the temperature necessary to induce collagen shrinkage was not observed within the disc. Temperatures sufficient to ablate nerves were developed in some areas but were not reliably produced in clinically relevant regions, such as the posterior annulus. These results suggest that beneficial clinical outcomes may be critically dependent on probe placement or other factors unknown.
A topographic study of posterior surface of the petrous pyramid was performed in 20 human cadaveri heads. The distances between the neurovascular structures were measured in the points where they contact the posterior surface of the petrous pyramid. The study also points out the relationship between the bone landmarks and the transverse and the superior petrous sinuses. The result of this study was correlated with the approaches to the cerebellopontine angle.