Search Results

You are looking at 1 - 10 of 22 items for

  • Author or Editor: Amir Samii x
  • Refine by Level: All x
  • Refine by Access: all x
Clear All Modify Search
Free access

nlm-article

Rudolf Fahlbusch and Amir Samii

Restricted access

nlm-article

Shizuo Oi, Amir Samii, and Madjid Samii

P A newly designed small-diameter rigid-rod neuroendoscope was created to evaluate the applicability of free-hand maneuvering during high-resolution imaging. The neuroendoscope was designed as a light, handheld tool weighing 550 g. A 20-cm-long objective lens, 2 mm in diameter, is placed in the lower two thirds of the single-space lumen of an oval-shaped outer sheath, 16.5 mm long and 3.5 × 2.5 mm at maximum diameter. Included are microinstruments of 1.3-mm diameter for various neuroendoscopic procedures, including microscissors, biopsy forceps, grasping forceps, monopolar coagulator/cutting rod, and bipolar coagulator that can be introduced through the upper one third of the lumen.

Because the endoscope is held steady in the surgeon's left hand, with the handle gripped at the base, quick back-and-forth movements can be made along the long axis, via a peel-away sheath inserted to the ventricle, shifting of the endoscope tip to the side of the objective target will be minimal. Given the instrument's unified configuration, the surgeon will never lose orientation during maneuvering. Using the farthest right of three inlet/outlet orifices, the short and handy semiflexible microinstruments can be guided and controlled by the surgeon's right hand.

After experience in 66 cases in which various neuroendoscopic procedures yielded excellent operative outcomes (morbidity rate in complications related to the endoscopic procedure 0%; mortality rate 0%), the endoscope prototype was finalized in the ideal form for frameless maneuvering that uses a rigid-rod endoscope. The “gun-butt” holder for use with the operator's left hand provides stability and allows the endoscope to be handled with improved control. These new aspects of the neuroendoscope and surgical technique offer substantial improvement over the flexible-steerable fiberoptic endoscopes.

Restricted access

nlm-article

Madjid Samii, Venelin M. Gerganov, and Amir Samii

Object

The authors evaluated the outcome of radical surgery in a consecutive series of patients with giant vestibular schwannomas (VSs).

Methods

Fifty patients with VSs > 4.0 cm in maximal extrameatal diameter were included in this retrospective study (Group A). The group was compared with a matched group of 167 patients with VSs < 3.9 cm (Group B). In all cases the retrosigmoid approach was used. Outcome measures included completeness of tumor removal, facial nerve function, hearing, and the surgery-related complication rate.

Results

The mean tumor size in Group A was 4.4 cm and that in Group B was 2.3 cm. Total removal was achieved in all Group A patients and in 97.6% of Group B patients. The anatomical integrity of the facial nerve was preserved in 92% in Group A and in 98.8% in Group B. At last follow-up 75% of the patients with giant VSs had excellent or good facial nerve function, 19% had fair function, and 6% had poor function. In 33% of patients (3 cases) with good preoperative hearing level, it was preserved. Newly developed lower cranial nerve dysfunction occurred in 3 patients but proved to be temporary in 2 of them. A CSF leak developed in 6% of those who not previously undergone surgery. Compared with Group B, a significant difference was found only in the rates of the following parameters: excellent facial nerve function, useful and good hearing, lower cranial nerve dysfunction, and blood collection (p < 0.05). The perioperative mortality rate in both groups was 0%.

Conclusions

In patients with a giant VS, total tumor removal can be achieved via the retrosigmoid approach with a 0% mortality rate and low morbidity rate, especially with regards to facial nerve function. In selected cases even hearing preservation is possible. Tumor size significantly correlates with postoperative outcome.

Restricted access

nlm-article

Amir Samii, Gustavo Adolpho Carvalho, and Madjid Samii

Object. Between 1994 and 1998, 44 nerve transfers were performed using a graft between a branch of the accessory nerve and musculocutaneous nerve to restore the flexion of the arm in patients with traumatic brachial plexus injuries. A retrospective study was conducted, including statistical evaluation of the following pre- and intraoperative parameters in 39 patients: 1) time interval between injury and surgery; and 2) length of the nerve graft used to connect the accessory and musculocutaneous nerves.

Methods. The postoperative follow-up interval ranged from 23 to 84 months, with a mean ± standard deviation of 36 ± 13 months. Reinnervation of the biceps muscle was achieved in 72% of the patients. Reinnervation of the musculocutaneous nerve was demonstrated in 86% of the patients who had undergone surgery within the first 6 months after injury, in 65% of the patients who had undergone surgery between 7 and 12 months after injury, and in only 50% of the patients who had undergone surgery 12 months after injury. A statistical comparison of the different preoperative time intervals (0–6 months compared with 7–12 months) showed a significantly better outcome in patients treated with early surgery (p < 0.05). An analysis of the impact of the length of the interposed nerve grafts revealed a statistically significant better outcome in patients with grafts 12 cm or shorter compared with that in patients with grafts longer than 12 cm (p < 0.005).

Conclusions. Together, these results demonstrated that outcome in patients who undergo accessory to musculocutaneous nerve neurotization for restoration of elbow flexion following brachial plexus injury is greatly dependent on the time interval between trauma and surgery and on the length of the nerve graft used.

Restricted access

nlm-article

Madjid Samii, Venelin Gerganov, and Amir Samii

Object

The aim of this study was to evaluate and present the results of current surgical treatment of vestibular schwannomas (VSs) and to report the refinements in the operative technique.

Methods

The authors performed a retrospective study of 200 consecutive patients who had undergone VS surgery over a 3-year period. Patient records, operative reports, follow-up data, and neuroradiological findings were analyzed. The main outcome measures were magnetic resonance imaging, neurological status, patient complaints, and surgical complications.

Complete tumor removal was achieved in 98% of patients. Anatomical preservation of the facial nerve was possible in 98.5% of patients. In patients treated for tumors with extension Classes T1, T2, and T3, the rate of facial nerve preservation was 100%. By the last follow-up examination, excellent or good facial nerve function had been achieved in 81% of the cases. By at least 1 year postsurgery, no patients had total facial palsy. In the patients with preserved hearing, the rate of anatomical preservation of the cochlear nerve was 84%. The overall rate of functional hearing preservation was 51%. There was no surgery-related permanent morbidity in this series of patients. Cerebrospinal fluid leakage was diagnosed in 2% of the patients. The mortality rate was 0%.

Conclusions

The goal of VS treatment should be total removal in one stage and preservation of neurological function, as they determine a patient’s quality of life. This goal can be safely and successfully achieved using the retrosigmoid approach.

Restricted access

nlm-article

Mario Giordano, Massimo Gallieni, Amir Samii, Concezio Di Rocco, and Madjid Samii

OBJECTIVE

Few cases of cerebellopontine angle (CPA) arachnoid cysts in pediatric patients have been described in the literature, and in only 2 of these cases were the patients described as suffering from hearing deficit. In this article, the authors report on 3 pediatric patients with CPA arachnoid cysts (2 with hearing loss and 1 with recurrent headaches) who underwent neurosurgical treatment at the authors’ institution.

METHODS

Four pediatric patients were diagnosed with CPA arachnoid cysts at the International Neuroscience Institute during the period from October 2004 through August 2012, and 3 of these patients underwent surgical treatment. The authors describe the patients’ clinical symptoms, the surgical approach, and the results on long-term follow-up.

RESULTS

One patient (age 14 years) who presented with headache (without hearing deficit) became asymptomatic after surgical treatment. The other 2 patients who underwent surgical treatment both had hearing loss. One of these children (age 9 years) had recent-onset hypacusia and experienced complete recovery immediately after the surgery. The other (age 6 years) had a longer history (2 years) of progressive hearing loss and showed an interruption of the deficit progression and only mild improvement at the follow-up visit.

CONCLUSIONS

CPA arachnoid cysts are uncommon in pediatric patients. The indication and timing of the surgical treatment are fundamental, especially when a hearing deficit is present.

Restricted access

nlm-article

Venelin M. Gerganov, Mario Giordano, Amir Samii, and Madjid Samii

Object

An increasing number of patients with vestibular schwannomas (VSs) are being treated with radiosurgery. Treatment failure or secondary regrowth after radiosurgery, however, has been observed in 2%–9% of patients. In large tumors that compress the brainstem and in patients who experience rapid neurological deterioration, surgical removal is the only reasonable management option.

Methods

The authors evaluated the relevance of previous radiosurgery for the outcome of surgery in a series of 28 patients with VS. The cohort was further subdivided into Group A (radiosurgery prior to surgery) and Group B (partial tumor removal followed by radiosurgery prior to current surgery). The functional and general outcomes in these 2 groups were compared with those in a control group (no previous treatment, matched characteristics).

Results

There were 15 patients in Group A, 13 in Group B, and 30 in the control group. The indications for surgery were sustained tumor enlargement and progression of neurological symptoms in 12 patients, sustained tumor enlargement in 15 patients, and worsening of neurological symptoms without evidence of tumor growth in 1 patient. Total tumor removal was achieved in all patients in Groups A and B and in 96.7% of those in the control group. There were no deaths in any group. Although no significant differences in the neurological morbidity or complication rates after surgery were noted, the risk of new cranial nerve deficits and CSF leakage was highest in patients in Group B. Patients who underwent previous radiosurgical treatment (Groups A and B) tended to be at higher risk of developing postoperative hematomas in the tumor bed or cerebellum. The rate of facial nerve anatomical preservation was highest in those patients who were not treated previously (93.3%) and decreased to 86.7% in the patients in Group A and to 61.5% in those in Group B. Facial nerve function at follow-up was found to correlate to the previous treatment; excellent or good function was seen in 87% of the patients from the control group, 78% of those in Group A, and 68% of those in Group B.

Conclusions

Complete microsurgical removal of VSs after failed radiosurgery is possible with an acceptable morbidity rate. The functional outcome, however, tends to be worse than in nontreated patients. Surgery after previous partial tumor removal and radiosurgery is most challenging and related to worse outcome.

Restricted access

nlm-article

Robert L. Martuza

Restricted access

nlm-article

Donald P. Becker

Restricted access

nlm-article

Venelin Gerganov, Hussam Metwali, Amir Samii, Rudolf Fahlbusch, and Madjid Samii

Object

An extensive craniopharyngioma is a tumor that extends into multiple compartments (subarachnoid spaces) and attains a size larger than 4 cm. A wide spectrum of approaches and strategies has been used for resection of such craniopharyngiomas. In this report the authors focused on the feasibility and efficacy of microsurgical resection of extensive craniopharyngiomas using a frontolateral approach.

Methods

A retrospective analysis was performed on 16 patients with extensive craniopharyngiomas who underwent operations using a frontolateral approach at one institution. The preoperative and postoperative clinical and radiological data, as well as the operative videos, were reviewed. The main focus of the review was the extent of radical tumor removal, early postoperative outcome, and approach-related complications.

Results

Gross-total resection of craniopharyngioma was achieved in 14 (87.5%) of 16 cases. Early after surgery (within 3 months), 1 patient showed improvement in hormonal status, while in the remaining 15 patients it worsened. No major neurological morbidity was observed. Two patients experienced temporary psychotic disorders. Visual function improved in 6 patients and remained unchanged in 9. One patient experienced a new bitemporal hemianopsia. Three patients with features of short-term memory disturbances at presentation did show improvement after surgery. There were no deaths or significant approach-related morbidity in this patient series. Only 1 patient required revision surgery for a CSF leak.

Conclusions

The safe and simple frontolateral approach provides adequate access even to extensive craniopharyngiomas and enables their complete removal with a reasonable morbidity and approach-related complication rate.