Microsurgical and histological identification and definition of an interdural incision zone in the dorsolateral cavernous sinus.

OBJECTIVES: The anatomy of the cavernous sinus is described controversially in a number of publications. In the present cadaveric study, the architecture of the dorsolateral wall of the cavernous sinus is studied microsurgically and histologically. MATERIALS AND METHODS: Twenty cadaveric skulls have been dissected through a classical surgical frontotemporal approach. The temporal skull base was flattened and anatomical landmarks like the meningo-orbital band, superior orbital fissure, foramina rotundum, ovale, and spinosum were identified. Lateral of the trigeminal foramina, the dura was cut and the periosteal dural layer was separated from the meningeal layer, identifying an interdural zone. The length and the extent of this zone were evaluated. The dural architecture of the interdural incision zone was examined histologically. RESULTS: In all specimens, two dural layers lateral of the trigeminal foramina could be separated. The identified interdural incision zone extended in a length of 3.8-6.4 cm in the antero-posterior direction. The zone could be followed medially to the superior orbital fissure for 5.3 mm and lateral of the foramen spinosum for 6.4 mm. The separation of the dural layers allowed the approach to the superior border of the cavernous sinus through this interdural incision zone. The histological analysis of the interdural incision zone showed clearly the existence of two dural layers. CONCLUSIONS: The architecture of the temporal-fossa-dura allows the microsurgical separation of two meningeal dural layers through a length of 5-6 cm next to the trigeminal foramina. Opening this interdural incision zone allowed exploring the superior border of the cavernous sinus.

Resection of an intramedullary high cervical metastasis from a malignant mixed Muellerian tumour.

We present a 66-year-old female patient with a high cervical intramedullary metastasis from a malignant mixed Muellerian tumour (MMMT; carcinosarcoma) with concomitant syringomyelia. She was admitted to our clinic with symptoms of cervical myelopathy. MRI revealed an intramedullary tumour of 2.6cm×1.2cm at the cervical vertebral body C2. We performed a laminectomy on C2 followed by a dorsal median myelotomy from C1 to C3 to resect the tumour. The surgical intervention removed the tumour completely and resolved the syringomyelia. During the 36months of follow-up, the patient presented in a stable condition with no evidence of tumour recurrence. To our knowledge, this is the first report of an intramedullary metastasis of a MMMT.

Terson haemorrhage in patients suffering aneurysmal subarachnoid haemorrhage: a prospective analysis of 60 consecutive patients.

OBJECTIVE: The concomitance of vitreous/subhyaloid haemorrhage (Terson syndrome; TS) and aneurysmal subarachnoid haemorrhage (aSAH) is commonly underestimated. The aim of this study was to determine the incidence of TS and to identify parameters that predispose its development, indicate the severity of the underlying disease, and predict outcome. METHODS: Sixty consecutive patients suffering from aSAH were included in this study. The admitting Glasgow Coma Scale scores (GCS), Hunt & Hess (H&H) and Fisher grades were documented. All participants were ophthalmologically examined. The outcome at discharge was estimated using the Glasgow Outcome Scale (GOS). RESULTS: Of the 60 patients admitted for aSAH, eleven (18.3%) displayed TS within 24h after aneurysm rupture. Statistical analysis revealed a significant relation between TS and either high Fisher- (3.0 vs. 2.32; p=0.008) or H&H- (4.09 vs. 2.69; p=0.001) and low GCS- (5.55 vs. 12.87; p<0.001) scores. Compared with the non-TS group, patients with TS displayed generally worse outcomes (mean GOS 2.09 vs. 3.53; p=0.007), including a significantly higher mortality (36.4 vs. 10.2%; p=0.028). CONCLUSION: Terson syndrome is likely to occur in severe aSAH with poor admission scores and indicates a worse functional outcome. An ophthalmological examination is strongly recommended in aSAH patients with poor admission scores.

Percutaneous placement of pedicle screws in the lumbar spine using a bone mounted miniature robotic system: first experiences and accuracy of screw placement.

STUDY DESIGN: A prospective analysis. OBJECTIVE: The idea of this study was to evaluate a new miniature robotic system providing passive guidance for pedicle screw placement at the lumbar spine. Special focus was laid on the postoperative accuracy of screw placement. SUMMARY AND BACKGROUND DATA: Recent technical developments lead to a minimization of pedicle screw fixation techniques. However, the use of navigational techniques is still under controversy. METHODS: Patients selected for a minimal invasive posterior lumbar interbody fusion received a spiral computer tomographic scan before surgery. The miniature hexapod robot was mounted to the spinous process and the system moves to the exact entry point according to the trajectory of the surgeon's preoperative plan. After minimal invasive screw placement all patients received routinely a postoperative spiral computer tomographic scan. Screws placed exactly within the pedicle were evaluated as group A, screws deviating <2 mm were evaluated as group B, > or =2 mm to <4 mm (group C); > or =4 mm to <6 mm (group D); and more than 6 mm (group E). RESULTS: Thirty-one patients received a PLIF with percutaneous posterior pedicle screw insertion using the bone mounted miniature robotic device. A total of 133 pedicle screws were placed. The majority of the screws were placed in L5 (58 screws; 43.6%). In axial plane, 91.7% of the screws were evaluated as group A and 6.8% were evaluated as group B. In longitudinal plane, 81.2% of the screws were evaluated as group A and 9.8% were evaluated as group B. In 1 screw (L5 right) the postoperative evaluation was done as group C (axial plane) and D (longitudinal plane). In 29/31 cases the integration of the miniature robotic system was successful. CONCLUSION: In our study the first clinical assessment of a new bone mounted robot system guiding percutaneous pedicle screw placement was done. A deviation <2 mm to the surgeon 's plan in 91.0% to 98.5% verifies the system's accuracy.

Successful resection of the recurrence of a cavernous malformation of the optic chiasm.

The case of a 33-year-old female who suffered from a recurrence of an intrachiasmatic cavernous malformation is presented. She had already undergone surgery in 1991 and 2001 and was admitted to our hospital with reduced vision in the right eye. After MRI, and diagnosis of recurrence of the cavernoma, a neurosurgical operation was performed using the pterional approach. The intraoperative situation was documented with micro photographs. The postoperative course was uneventful. The female described a minimal improvement of her vision. No postoperative complications were observed. To our knowledge, microsurgically complete extirpation of a recurrence of an intrachiasmatic cavernoma has not yet been reported in the literature.