A Case Series of Stereotactic Biopsy of Brainstem Lesions through the Transfrontal Approach.

Background and Importance Brainstem lesions may be unresectable or unapproachable. Regardless, the histopathological diagnosis is fundamental to determine the most appropriate treatment. We present our experience with transfrontal stereotactic biopsy technique for brainstem lesions as a safe and effective surgical route even when contralateral transhemispheric approach is required for preservation of eloquent tissue. Clinical Presentation Twenty-five patients underwent surgery by transfrontal approach. Medical records were reviewed for establishing the number of patients who had postoperative histopathological diagnosis and postoperative complications. Twenty-four patients (18 adults and 7 children) had histopathological diagnosis. There were 18 astrocytomas documented, of which 12 were high grade and 6 low grade. The other diagnoses included viral encephalitis, post-renal transplant lymphoproliferative disorder, nonspecific chronic inflammation, Langerhans cell histiocytosis, and two metastases. No case was hindered by cerebrospinal fluid loss or ventricular entry. Complications included a case of mesencephalic hemorrhage with upper limb monoparesis and a case of a partially compromised third cranial nerve in another patient without associated bleeding. Conclusion Stereotactic biopsy of brainstem lesions by transfrontal ipsilateral or transfrontal transhemispheric contralateral approaches is a safe and effective surgical approach in achieving a histopathological diagnosis in both pediatric and adult populations.

Preservation of frontal white matter tracts in ventricular surgery: favoring an anterior interhemispheric transcallosal approach vs a transcortical transfrontal transventricular approach.

Secondary to the creation of a surgical corridor and retraction, white matter tracts degenerate, causing long-term scarring with potential neurological consequences. Third and lateral ventricle tumors require surgery that may lead to cognitive impairment. Our objective is to compare the long-term consequences of a transcortical transfrontal approach and an interhemispheric transcallosal approach on corpus callosum and frontal white matter tracts degeneration. Surgical patients with ventricular tumor accessible through both approaches were included and clinico-radiological data were retrospectively analyzed. The primary endpoint was the callosotomy length at 3-month post-operative T1 MRI, corrected by the extension of the tumor and the use of neuronavigation. Secondary outcomes included perioperative criteria such as bleeding, use of retractors and duration, FLAIR hypersignal on 3-month MRI, and re-do surgeries. To assess white matter tract interruption, 3-month FLAIR hypersignal was superposed to a tractography atlas. Seventy patients were included, 57 (81%) in the transfrontal group and 13 (19%) in the interhemispheric group. There was no difference in the mean callosotomy length on 3-month MRI (12.3 mm ± 5.60 transfrontal vs 11.7 mm ± 3.92 interhemispheric, p = 0.79) on univariate and multivariate analyses. The callosotomy length was inferior by - 3.13 mm for tumors located exclusively in the third ventricle (p = 0.016), independent of the approach. Retractors were used more often in transfrontal approaches (60% vs 33%, p < 0.001). The extent of frontal FLAIR hypersignal was higher after transfrontal approach (14.1 mm vs 0.525 mm, p < 0.001), correlated to the use of retractors (p < 0.05). After the interhemispheric approach, no tract other than corpus callosum was interrupted, whereas, after the transfrontal approach, frontal arcuate fibers and projections from the thalamus were interrupted in all patients, the cingulum in 19 (33%), the superior fronto-occipital fasciculus in 15 (26%), and the superior longitudinal fasciculus in 2 (3%). Transfrontal and interhemispheric approaches to the third and lateral ventricles both lead to the same long-term damage to the corpus callosum, but the transfrontal approach interrupts several white matter tracts essential to cognitive tasks such as attention and planning, even in the non-dominant hemisphere. These results encourage all neurosurgeons to be familiar with both approaches and favor the interhemispheric approach when both can give access to the tumor with a comparable risk. Neuropsychological studies are necessary to correlate these anatomical findings to cognitive outcomes.

Rediscovery of the transcerebellar approach: improving the risk-benefit ratio in robot-assisted brainstem biopsies.

OBJECTIVE: Conventional frame-based stereotaxy through a transfrontal approach (TFA) is the gold standard in brainstem biopsies. Because of the high surgical morbidity and limited impact on therapy, brainstem biopsies are controversial. The introduction of robot-assisted stereotaxy potentially improves the risk-benefit ratio by simplifying a transcerebellar approach (TCA). The aim of this single-center cohort study was to evaluate the risk-benefit ratio of transcerebellar brainstem biopsies performed by 2 different robotic systems. In addition to standard quality indicators, a special focus was set on trajectory selection for reducing surgical morbidity. METHODS: This study included 25 pediatric (n = 7) and adult (n = 18) patients who underwent 26 robot-assisted biopsies via a TCA. The diagnostic yield, complication rate, trajectory characteristics (i.e., length, anatomical entry, and target-point location), and skin-to-skin (STS) time were evaluated. Transcerebellar and hypothetical transfrontal trajectories were reconstructed and transferred into a common MR space for further comparison with anatomical atlases. RESULTS: Robot-assisted, transcerebellar biopsies demonstrated a high diagnostic yield (96.2%) while exerting no surgical mortality and no permanent morbidity in both pediatric and adult patients. Only 3.8% of cases involved a transient neurological deterioration. Transcerebellar trajectories had a length of 48.4 ± 7.3 mm using a wide stereotactic corridor via crus I or II of the cerebellum and the middle cerebellar peduncle. The mean STS time was 49.5 ± 23.7 minutes and differed significantly between the robotic systems (p = 0.017). The TFA was characterized by longer trajectories (107.4 ± 11.8 mm, p < 0.001) and affected multiple eloquent structures. Transfrontal target points were located significantly more medial (-3.4 ± 7.2 mm, p = 0.042) and anterior (-3.9 ± 8.4 mm, p = 0.048) in comparison with the transcerebellar trajectories. CONCLUSIONS: Robot-assisted, transcerebellar stereotaxy can improve the risk-benefit ratio of brainstem biopsies by avoiding the restrictions of a TFA and conventional frame-based stereotaxy. Profound registration and anatomical-functional trajectory selection were essential to reduce mortality and morbidity.

Transfrontal and Transsphenoidal Approaches to Pediatric Craniopharyngioma: A National Perspective.

INTRODUCTION: This study compared transsphenoidal (TS) and transfrontal (TF) approaches to craniopharyngioma utilizing a national database. METHODS: The Kids' Inpatient Database (2003, 2006, and 2009) was surveyed for patients with a diagnosis of craniopharyngioma who underwent a subset of surgical interventions to compare TS and TF surgery. Demographics, hospital variables, and complications/comorbidities were analyzed with multivariate regression. RESULTS: 314 admissions (TS = 104, TF = 210) were identified. The mean age was 14.8 (TS) versus 9.8 (TF) years (p < 0.001). The mean number of diagnoses was 4.6 (TS) versus 6.2 (TF) (p < 0.001). Diabetes insipidus was associated with 38% (TS) and 69% (TF). Cerebrospinal fluid (CSF) leak affected 19% TS and 4% TF resections. Other complications and comorbidities included postoperative stroke (2% TS vs. 5% TF), panhypopituitarism (5 vs. 8%), death (0 vs. 1%), cranial nerve deficits (1 vs. 6%), thrombotic events (7 vs. 17%), and seizures (0 vs. 12%). 98% of patients were discharged home after a mean 6-day length of stay (LOS) after TS, whereas 90% of TF patients had a LOS of 12 days. TS cases were more likely to be privately insured (68%) and from higher income brackets (61%) than TF ones (56 and 2%, respectively) (p < 0.05). In multivariate regression models adjusting for age, sex, race, number of diagnoses, surgical approach, hospital volume, and insurance type, the TS approach was associated with an increased incidence of CSF leak (OR 10, p < 0.001). More documented diagnoses (OR 16-60, p < 0.01) and TF approach (OR 2.6, p < 0.01) were associated with an increased incidence of other complications and comorbidities. Age younger than 10 (ß-coefficient 2.3, p = 0.01), more diagnoses (ß-coefficient 1.2, p < 0.001), and TF approach (ß- coefficient 3.0, p < 0.01) were associated with increased LOS. A higher number of diagnoses were associated with nonhome discharge destinations (ß-coefficient 1.29, p < 0.001). CONCLUSION: TS surgery was associated with an increased incidence of CSF leak but shorter LOS; TF surgery was associated with an increased incidence of other complications. Patients undergoing TS surgery were more likely to have private insurance and a higher family income bracket.

Mucocele of the Frontal Sinus: Report of Two Cases

We report two cases of mucocele of the frontal sinus presenting with exophthalmos and diplopia. Total removal involved the transfrontal approach and neurological deficits were eliminated. Details of clinical manifestations are presented, and a review of the literature is included.

Mucocele of the Frontal Sinus: Report of Two Cases

We report two cases of mucocele of the frontal sinus presenting with exophthalmos and diplopia. Total removal involved the transfrontal approach and neurological deficits were eliminated. Details of clinical manifestations are presented, and a review of the literature is included.