Transsphenoidal surgery is a common surgical approach for intrasellar lesions with or without suprasellar extension, i.e., pituitary tumors or Rathke cleft cysts. The microscopic sublabial transsphenoidal approach was originally established by Hardy, J. Thereafter, various modifications, such as the transnasal transsphenoidal approach and the endoscopy-assisted microscopic transsphenoidal approach were employed. Nowadays, a sole endoscopic transsphenoidal approach has been widely used not only for those lesions, but also for skull base tumors. In this article, the basic principles of the microscopic sublabial and transnasal transsphenoidal approaches are described in a step-by-step fashion as a review for younger neurosurgeons. As some modifications can be readilly used in the microscopic transsphenoidal approaches, those are also explained. When performing a re-operation for recurrent pituitary tumor, several tips are necessary for a successful outcome, and these are precisely presented here as well. In conclusion, each surgical approach has its advantages and disadvantages. But armed with a full and thorough understanding of each approach, experienced neurosurgeons can confidently select the safest and most appropriate approach for each patient.

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  The orbitozygomatic approach (OZA) and extradural temporopolar approach (EDTPA) are standard skull base techniques to access the central skull base from the anterolateral direction. This study discusses operative techniques and tips for these approaches.
  The OZA provides wide operative field and working angle. Frontozygomatic osteotomy based on creating guide burr holes in the orbital wall and cutting bone using a diamond-coated threadwire saw is safe and results in minimum bone gap in the malar eminence.
  The EDTPA provides a surgical corridor to the interpeduncular cistern via the opened cavernous sinus. Peeling of the dura propria from the lateral wall of the cavernous sinus is started at the surgically exposed junction between the dura propria and the inner membrane between the superior orbital fissure and foramen rotundum instead of cutting the dura propria to avoid injuring the cranial nerves.

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  The transpetrosal approach, involving resection of the petrous bone to various degrees, provides different levels of access to the petroclival region. According to the area and degree of petrous bone removal, the transpetrosal approach can roughly be divided into an anterior, posterior and their combined approach. Factors considered to be important in determining the selection of approach include the size, location, and extension of the lesion, preoperative hearing evaluation, and the anatomy of the venous sinuses. In this paper, the technical basis of the transpetrosal approach is described with respect to several important factors to avoid surgical complications related to this approach.

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  The lateral suboccipital retrosigmoid approach, one of the common procedures used in neurosurgical operations, is indicated for lesions at the cerebellopontine angle (CPA). The location of the craniotomy varies according to the main location of the pathology in the superior, middle, or inferior CPA. Here we introduce the basic procedure of the technique and its variations.
  First, the diagnosis of the pathology, and the relationship between the sutures and sinuses should be confirmed by preoperative magnetic resonance imaging (MRI) and computed tomography (CT). Three-dimensional MRI-CT fusion images are a great help in performing secure operative planning. Neuromonitoring techniques using cranial nerve stimulators or auditory evoked potentials, are also essential for CPA surgery. The lateral positioning obtained, with suitable head fixation, is especially important. Two different skin incisions, either a lazy “S” or “V” shaped, are used in consideration of the hair pattern of the patient. The bulk of the posterior nuchal muscles are caudally reflected, to avoid damaging them, which prevents postoperative shoulder stiffness and muscle contraction headaches.
  Performing the appropriate craniotomy is also key for a successful outcome. A superior CPA approach is taken for lesions around the trigeminal nerve, a middle CPA approach is used for pathological conditions around the auditory and facial nerves, and an inferior CPA approach is best for lesions around the lower cranial nerves and the pontomedullary junction. A high-speed drill and kerrison rongeurs are used for the craniotomy in order to obtain secure exposure of the posterior margin of the sigmoid sinus and to maximally preserve the autologous bone. The opening of the foramen magnum and removal of the posterior arch of the C1 are not necessary ; however, a transcondylar or extreme lateral approach should be considered when a more ventrocaudal visual axis is required. For intradural procedures, careful attention should be paid to the preservation of the veins, direction of the optic axis of the microscope, and circulation of the cerebrospinal fluid.
  In conclusion, there are three basic craniotomies of the lateral suboccipital retrosigmoid approach, which broadly correspond to addressing pathological conditions in the superior, middle, and inferior CPA.

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  Here, we summarize the surgical nuances of the occipital transtentorial approach (OTA). OTA provides wider access and good visualization of the dorsal midbrain or pineal lesions. On the other hand, postoperative temporary or permanent visual field deficits are the most frequent complications. To avoid such complications, selection of the appropriate side to avoid venous congestion by excessive retraction of the occipital lobe, wide dissection of interhemispheric fissure, gentle retraction and anatomical-mechanical protection of the occipital lobe, careful dissection of the arachnoid around the lesion, and patient monitoring using visual evoked potentials are important technical points to consider. Midbrain injury and venous injury can also cause serious neurological deficits and should be avoided by employing meticulous technique. The importance of careful imaging analysis prior to surgery, appropriate anatomical knowledge, and meticulous surgical technique are also stressed.

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  Options for posterior decompression in cases of cervical spondylotic myelopathy comprise laminectomy and laminoplasty ; however, the relative merits of each have yet to be fully determined. At our institution, laminectomy is the treatment of choice for patients with cervical spondylotic myelopathy who are elderly or maintain their physiological lordosis. The present study investigated the outcomes of microsurgical laminectomy performed at our institution.
  A total of 20 patients with cervical spondylotic myelopathy who underwent microsurgical laminectomy at our institution between April 2004 and June 2010 and who were available for follow-up for at least one year was investigated. Pre-and postoperative C2-7 angle, cervical vertebral range of motion (cervical ROM), local angle, and neurosurgical cervical spine scale (NCSS) scores were compared.
  Postoperatively, kyphosis was absent, and cervical ROM and local angle were significantly reduced with a statistically significant difference. NCSS scores also improved. The postoperative braking effect is thought to have contributed to the reduced cervical vertebral instability.
  In conclusion, microsurgical laminectomy achieves favorable outcomes for cervical spondylotic myelopathy.

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  Many neurological disorders cause neurogenic bladder dysfunction. However, cervical disc herniation is not readily known to cause neurogenic bladder dysfunction without sensorimotor symptoms. A 58-year-old female suffered from urinary incontinence while walking and a severe urinary urgency or urinary retention after 2-hour cervical flexion for 3 years. About 2.5 years after the onset of these symptoms, she experienced a disturbance of sensation and elaborate movements in both upper limbs, whose cause was diagnosed as a C4/5 central prolapsed disc herniation as revealed by MR images. C4/5 anterior cervical decompression and fusion were performed, and all of her neurological symptoms including bladder dysfunction improved. This case suggests that it is worthwhile considering the possibility of cervical spinal disorders even in a case of neurogenic bladder dysfunction without sensorimotor complaints.

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