A marginal process of the zygomatic bone predicts a lateral exit of the zygomaticotemporal nerve: An anatomical study with application to surgery around the midface.

Previous studies have not verified the contents of accessory foramina of the zygomatic bone on dry skulls and thus could not conclude whether they carried accessory zygomaticofacial nerve branches or branches or the entire trunk of the zygomaticotemporal nerve (ZTN). Therefore, the aim of the current study is to present findings from cadaveric dissections to clarify this relationship. Fifty, fresh frozen, adult cadaveric sides underwent dissection of the ZTN. When identified, these nerves were quantified and their relationship to the zygomatic bone further documented by dissecting through the bone following the course of the nerve from a superficial to deep perspective. Additionally, 100 dry, adult, human skulls were analyzed looking for lateral foramina on the zygomatic bone. On three cadaveric sides (6%), the ZTN was found to pierce the zygomatic bone deeply and exit its superficial lateral surface. For dry skull specimens, a lateral zygomaticotemporal foramen (ZTF) was identified on nine sides (4.5%). For both groups, the presence of a strong marginal process of the zygomatic bone was strongly correlated to a ZTF exiting the lateral surface of the zygomatic bone. Although relatively uncommon, the ZTN can pierce the lateral aspect of the zygomatic bone and thus can be located superficial to the cheek. Such findings should be borne in mind during surgical or other invasive procedures in this area in order to minimize iatrogenic injury to the ZTN.

Prevalence of Petrooccipital Fissure Fusion: Osteological Study with Application to Approaches to the Skull Base and Imaging Interpretation.

INTRODUCTION: The petrooccipital fissure (POF) has relevance to skull base approaches, various tumors and craniosynostoses, and some cases of age-related hearing loss. However, the prevalence of fusion and classification of such is rarely found in the extant medical literature. METHODS: One-hundred and 10 dry human skulls (220 sides) were used for this study. The skulls were evaluated for fusion of the POF. Both the endocranial and exocranial aspects of the POF were analyzed. A classification scheme was developed to better describe the location of POF fusion. RESULTS: A fused POF was identified on 36 sides (16.4%) and commonly found bilaterally (11%). Of these, 30 sides (83.3%) were completely fused (type I) and 6 sides (2.7%) were partially fused (types II and III). For the partially fused fissures, the fused part was on all but 2 sides with the most anterior portion of the petrous part of the temporal bone and adjacent clivus (type II). For the 2 sides (both right sides), the fusion was more posteriorly located between the petrous part of the temporal bone and lateral clivus (type III). Fusion of the POF was more often found in specimens with a partially or fully ossified petroclival ligament. Completely fused POF was positively correlated to sides with an intrajugular bony septum. CONCLUSIONS: A POF fusion was relatively common and associated with an ossified petroclival ligament and intrajugular bony septation. Such a prevalence is important for clinicians and skull base surgeons interpreting imaging of the skull base.

Role of Surgery in Spinal Metastases.

Spinal metastases constitute two-third of all cases of bone metastases. Surgical intervention in these tumours has been recommended in highly selective cases, for confirming diagnosis, stabilizing the spine, and decompressing nerves or spinal cord for alleviation of pain and preservation of function.In this article,the authors have reviewed available evidence on role of surgery in spinal metastases and have presented results of selected papers on this vast topic.