Lateral Suboccipital Research Articles

Tailored Surgical Approaches for Foramem Magnum Tumors

Objective To describe our surgical techniques, analyze their safety and their postoperative outcomes for foramen magnum tumors (FMTs). Methods From 1986 to 2014, 34 patients with FMTs underwent surgeries using either the lateral suboccipital approach, standard midline suboccipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions. Results In the present series, there were 22 (64.7%) female and 12 (35.2%) male patients. The age of the patients ranged from 12 to 63 years old. We observed 1 operative mortality (2.9%). A total of 28 patients (82.3%) achieved a score of 4 or 5 in the Glasgow Outcome Scale (GOS). Gross total resection (GTR) was obtained in 22 (64.7%) patients. After the surgery, 9 (26%) patients developed lower cranial nerve dysfunction (LCNd) weakness. The follow-up varied from 1 to 24 years (mean: 13.2 years). Conclusion The majority of tumors located in the FM can be safely and efficiently removed using either the lateral sub occipital approach, standard middle line sub occipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions.

Simple Lateral Suboccipital Approach and Modification for Vertebral Artery Aneurysms: A Study of 52 Cases Over 10 Years.

Complex skull base approaches are frequently used to treat intracranial vertebral artery (VA) and proximal posterior inferior cerebellar artery (PICA) aneurysms. These complex procedures are associated with higher risk of neurovascular injury. Hence, a less-invasive surgical approach is needed to improve the efficacy and safety of treatment. A retrospective analysis was conducted on clinical and radiologic data from surgeries in which simple lateral suboccipital and "lateral-enough" approaches were used to clip VA aneurysms in the Department of Neurosurgery at Helsinki University Central Hospital from 2000 to2009. Fifty-two VA or PICA aneurysms were treated using the simple lateral suboccipital approach. Sixteen patients (31%) presented with an unruptured aneurysm, 21 patients (40%) with World Federation of Neurosurgical Societies (WFNS) grade 1-3, and 15 patients (29%) with World Federation of Neurosurgical Societies grade 4-5. The aneurysms were saccular in 48 cases (92%), dissecting in 3 cases (6%), and fusiform in 1 case (2%). The most common aneurysm location was the VA-PICA junction (81%). The mean final modified Rankin Scale score was 2, and in unruptured cases, all patients had favorable clinical outcomes. The main causes of unfavorable outcome were poor preoperative clinical grade (P= 0.002), preoperative intraventricular hemorrhage (P= 0.008), postoperative hydrocephalus (P= 0.003), brain infarction (P= 0.005), and postoperative pneumonia (P < 0.001). We describe a 10-year experience using a simple lateral suboccipital approach and its modification by the senior author (J.H.) to treat VA and proximal PICA aneurysms. Unfavorable outcome was related to the poor preoperative clinical grade, preoperative intraventricular hemorrhage, and postoperative pneumonia.

Relationship Between Muscle Dissection Method and Postoperative Muscle Atrophy in the Lateral Suboccipital Approach to Vestibular Schwannoma Surgery

Various techniques are available for occipital skull exposure with muscle dissection, as well as different types of skin incisions in the lateral suboccipital approach to vestibular schwannoma (VS) surgery. The skin incisions are generally classified as S-shaped, J-shaped, or C-shaped. In each method, the technique used for muscle dissection differs in terms of cut, single layer, and multiple layers. This study was performed to identify the relationships among muscle dissection method, skin incision type, and muscle atrophy in the lateral suboccipital approach to surgery for VS. Between 2002 and 2011, we performed surgical resection in 53 patients with VS at Shinshu University Hospital. Of these 53 patients, 35 with radiographic annual follow-up for >3 years after surgery were evaluated retrospectively. These patients included 14 who underwent an S-shaped incision, 6 with a J-shaped incision, and 15 with a C-shaped incision. Bilateral areas of the skin and occipital muscles were measured, and rates of atrophy were calculated and compared among the 3 methods. Postoperative muscle atrophy was significantly advanced in the second postoperative year, but did not tend to develop further after the third year. The postoperative muscle atrophy ratio was significantly lower in the C-shaped incision group (mean ± SD, 4.0% ± 6.9%) compared with the S-shaped (17.1% ± 9.8%) and J-shaped (17.6% ± 10.0%) incision groups within 2 years after surgery (P < 0.05). The C-shaped skin incision with multilayer muscle dissection was associated with significantly reduced postoperative muscle atrophy compared with the other methods.

Modified Technique for Primary Dural Closure in the Lateral Suboccipital Approach:Dural Moisturizing with Fibrin Glue Coating

When employing the lateral suboccipital approach, the thin dura shrinks due to the drying effect of illumination and air exposure, and dural substitutes are often needed for closure. We developed a new technique involving dural moisturizing with fibrin glue coating that facilitates primary dural closure. We used this technique in 12 adults who underwent the lateral suboccipital approach for 5 hemifacial spasms, 3 trigeminal neuralgias, 2 cerebellopontine meningiomas, 1 vestibular schwannoma, and 1 vertebral artery aneurysm. Fibrin glue was sprayed on the outer surface before opening the dura, and additionally sprayed on the inner surface of the reflected dural flap after opening the dura. After the intradural procedures the dura was closed with the usual knotted sutures. Dural closure was performed 65-340 minutes (mean: 161.9 minutes) post-durotomy. This technique resulted in primary dural closure with a sufficient area of preserved dura in all but one patient. In this patient, the dura shrank due to coagulation of the dural attachment to the meningioma for which a small autologous substitute was required. There were no procedure-related complications such as cerebrospinal fluid leakage and meningitis. Dural moisturizing with fibrin glue coating is simple, protects the dura from drying and shrinkage, and facilitates primary dural closure in patients undergoing the lateral suboccipital approach.

Strategies to Prevent Positioning-Related Complications Associated with the Lateral Suboccipital Approach

The lateral positioning used for the lateral suboccipital surgical approach is associated with various pathophysiologic complications. Strategies to avoid complications including an excessive load on the cervical vertebra and countermeasures against pressure ulcer development are needed. We retrospectively investigated positioning-related complications in 71 patients with cerebellopontine angle lesions undergoing surgery in our department between January 2003 and December 2010 using the lateral suboccipital approach. One patient postoperatively developed rhabdomyolysis, and another presented with transient peroneal nerve palsy on the unaffected side. Stage I and II pressure ulcers were noted in 22 and 12 patients, respectively, although neither stage III nor more severe pressure ulcers occurred. No patients experienced cervical vertebra and spinal cord impairments, brachial plexus palsy, or ulnar nerve palsy associated with rotation and flexion of the neck. Strategies to prevent positioning-related complications, associated with lateral positioning for the lateral suboccipital surgical approach, include the following: atraumatic fixation of the neck focusing on jugular venous perfusion and airway pressure, trunk rotation, and sufficient relief of weightbearing and protection of nerves including the peripheral nerves of all four extremities.

Osteoplastic Lateral Suboccipital Approach for Acoustic Neuroma Surgery: Technical Note

OBJECTIVE Persistent headache remains a significant problem in a small group of patients after acoustic neuroma surgery via the lateral suboccipital approach. We describe a modified technique of osteoplastic lateral suboccipital craniotomy for surgery of the cerebellopontine angle. This simple and elegant technique provides a superior cosmetic result and a significant reduction in patients’ symptoms. METHODS We report on our series of 75 patients who underwent surgery for acoustic neuroma. The maximal follow-up period was 4 years. RESULTS No patients reported headache postoperatively. Cerebrospinal fluid fistulae were not observed. CONCLUSION This modified approach minimizes cerebellar retraction, and the neural and vascular structures can be preserved under direct visualization of the tumor. This lateral suboccipital approach is a useful modification of previous approaches in acoustic neuroma surgery. It provides successful tumor resection and excellent functional results.

Osteoplastic lateral suboccipital approach for acoustic neuroma surgery.

Persistent headache remains a significant problem in a small group of patients after acoustic neuroma surgery via the lateral suboccipital approach. We describe a modified technique of osteoplastic lateral suboccipital craniotomy for surgery of the cerebellopontine angle. This simple and elegant technique provides a superior cosmetic result and a significant reduction in patients' symptoms. We report on our series of 75 patients who underwent surgery for acoustic neuroma. The maximal follow-up period was 4 years. No patients reported headache postoperatively. Cerebrospinal fluid fistulae were not observed. This modified approach minimizes cerebellar retraction, and the neural and vascular structures can be preserved under direct visualization of the tumor. This lateral suboccipital approach is a useful modification of previous approaches in acoustic neuroma surgery. It provides successful tumor resection and excellent functional results.