The transmaxillary endoscopic approach to the orbit

Objective

In this surgical-anatomical cadaveric study we investigate the feasibility of the transmaxillary endoscopic approach to the intraorbital space. Anatomical landmarks are defined, the endoscopic view in the orbital space is studied and complications that can occur are discussed.

Methods

Nine formalin-fixed heads were used to study the transmaxillary endoscopic approach to the orbit. The approach was used twice on each head (once for each maxilla). Therefore, we report our results on 18 transmaxillary intraorbital approaches. For better differentiation of anatomical structures, the veins and arteries were injected with blue and red plastic respectively in six cadaveric heads.

Results

The transmaxillary approach enables viewing the inferior intraconal structures without endangering the infraorbital nerve and its artery and without diversion of the inferior rectus muscle. The optic nerve was visualised more easily through the approach medial to the inferior rectus muscle instead of lateral to the muscle since the ciliary nerves are in the way in the lateral approach. The combination of the approaches medial and lateral to the inferior rectus muscle allows very good identification of all important anatomical structures in the inferior intraconal space.

Conclusion

The transmaxillary endoscopic approach to the orbit is a useful new approach in the surgical armamentarium for orbital lesions. The overview of the inferior part of the orbit is excellent, and the lateral part of the optic nerve can be visualised. Careful anatomical dissection allows visualisation of important anatomical structures in the orbit without damaging nerves or arteries.     

How I do it: Endoscopic endonasal approach for odontoid resection

Background

Since it was first described in 2005 by Kassam et al., the technique of endoscopic resection of the odontoid by the transnasal route has gained broad acceptance. Its advantages over the transoral approach are currently well-demonstrated.

How I do it: the endoscopic endonasal optic nerve and orbital apex decompression

Background

With the refinement of the technique, endoscopic endonasal surgery increases its field of indications. The orbital compartment is among the locations easily reached through the nostril. This anteromedial approach has been described primarily for inflammatory or traumatic diseases, with few data for tumoral diseases.

Method

Since 2010, this route has been used at our institution either for decompression or for biopsy of orbital tumoral diseases.

Findings/Conclusions

Even if further studies are warranted, this strategy proved to be beneficial for patients, with improvements in visual outcome. In this article, the authors summarize their technique and their experience with endonasal endoscopic orbital decompression. Key points ? Nasal and sphenoidal anatomies determine the feasibility and risks for doing an efficient medial optic or orbit decompression. ? Techniques and tools used are those developed for pituitary surgery. ? A middle turbinectomy and posterior ethmoidectomy are mandatory to expose the medial wall of the orbit. ? The Onodi cell is a key marker for the optic canal and must be opened up with caution. ? The lamina papyracea is opened first with a spatula and the optic canal opened up by a gentle drilling under continuous irrigation from distal to proximal. ? Drilling might always be used under continuous irrigation to avoid overheating of the optic nerve. An ultrasonic device can be used as well. ? The nasal corridor is narrow and instruments may hide the infrared neuronavigation probe. To overcome this issue, a magnetic device could be useful. ? Doppler control could be useful to locate the ICA. ? The optic canal must be opened up from the tuberculum of the sella to the orbital apex and from the planum (anterior cranial fossa) to the lateral OCR or ICA canal ? At the end of the procedure, the optic nerve becomes frequently pulsatile, which is a good marker of decompression.     

How I do it: Laparoscopic cholecystectomy

Laparoscopic cholecystectomy, although new, has enjoyed a rapid acceptance around the world. This article describes our initial experience with this procedure. Training and credentialing, including attending of courses, are important to ensure competency in this technique prior to independent performance of this operation; our guidelines are outlined. Our indications for laparoscopic chlecystectomy are no different from those for open surgery and some previously considered contraindications to laparoscopic cholecystectomy have now been dropped. Our preoperative work up and operative technique are discussed. From June 1991 to December 1992, we performed and analyzed 304 laparoscopic cholecystectomies, including 66 cases of inflamed gallbladders in our department. Preoperative endoscopic retrograde cholangiopancreatography (ERCP) was done only in patients suspected of having bile duct stones. This resulted in 0.9% needing postoperative ERCP stone extraction. The procedure was completed in 91.4% of patients, with a conversion rate of 3% for elective and 28% for emergency patients. Bile duct injury occurred in 1.4% of patients and minor complications in 4%. The use of laparoscopic cholecystectomy is growing in our region. As experience increases and more emergency cholecystectomies are done, the proportion of all cholecystectomies done laparoscopically will increase rapidly. Offprint requests to: P. Goh     

The LeFort I transmaxillary approach to skull base tumors

This article discusses the surgical approach using the LeFort I and its variations to the extracranial skull base for removal of craniocervical lesions from the sphenoid to the fourth cervical vertebra between the carotids. Clival lesions with superior and inferior extension and nasopharyngeal lesions can be accessed by this approach. The outcome of surgical, radiation, and chemotherapeutic treatment is beyond the scope of this brief article, which focuses on the technical aspects of cranial base tumor exposure.     

Radical retropubic prostatectomy: How I do it

Prostate cancer has become one of the leading cancers affecting men in Hong Kong. Radical prostatectomy remains the ideal treatment for the cure of prostate cancer. Evolution in the technique of radical prostatectomy, based on a better understanding of the periprostatic anatomy, has reduced operative morbidity in terms of blood loss, incontinence and impotence, and has rendered radical retropubic prostatectomy a safe operation and the standard surgical approach.     

How I do it: epidural anterior petrosectomy

Background  

Among the potential approaches to access the petroclival area, epidural anterior petrosectomy (EAP) appears to be the most direct and conservative transpetrous route. In this article, we aim to detail the relevant surgical steps necessary to perform EAP in a reproducible and safe manner.