Peter G. Campbell and James J. Evans
Juan C. Fernandez-Miranda, James J. Evans, Paul A. Gardner, Carl H. Snyderman, and Pablo F. Recinos
Tyler J. Kenning, Thomas O. Willcox, Gregory J. Artz, Paul Schiffmacher, Christopher J. Farrell, and James J. Evans
Thinning of the tegmen tympani and mastoideum components of the temporal bone may predispose to the development of meningoencephaloceles and spontaneous CSF leaks. Surgical repair of these bony defects and associated meningoencephaloceles aids in the prevention of progression and meningitis. Intracranial hypertension may be a contributing factor to this disorder and must be fully evaluated and treated when present. The purpose of this study was to establish a treatment paradigm for tegmen defects and elucidate causative factors.
The authors conducted a retrospective review of 23 patients undergoing a combined mastoidectomy and middle cranial fossa craniotomy for the treatment of a tegmen defect.
The average body mass index (BMI) among all patients was 33.2 ± 7.2 kg/m2. Sixty-five percent of the patients (15 of 23) were obese (BMI > 30 kg/m2). Preoperative intracranial pressures (ICPs) averaged 21.8 ± 6.0 cm H2O, with 10 patients (43%) demonstrating an ICP > 20 cm H2O. Twenty-two patients (96%) had associated encephaloceles. Five patients underwent postoperative ventriculoperitoneal shunting. Twenty-two CSF leaks (96%) were successfully repaired at the first attempt (average follow-up 10.4 months).
Among all etiologies for CSF leaks, those occurring spontaneously have the highest rate of recurrence. The surgical treatment of temporal bone defects, as well as the recognition and treatment of accompanying intracranial hypertension, provides the greatest success rate in preventing recurrence. After tegmen dehiscence repair, ventriculoperitoneal shunting should be considered for patients with any combination of the following high-risk factors for recurrence: spontaneous CSF leak not caused by another predisposing condition (that is, trauma, chronic infections, or prior surgery), high-volume leaks, CSF opening pressure > 20 cm H2O, BMI > 30 kg/m2, preoperative imaging demonstrating additional cranial base cortical defects (that is, contralateral tegmen or anterior cranial base) and/or an empty sella turcica, and any history of an event that leads to inflammation of the arachnoid granulations and impairment of CSF absorption (that is, meningitis, intracranial hemorrhage, significant closed head injury, and so forth).
Tyler J. Kenning, D. David Beahm, Christopher J. Farrell, Madeleine R. Schaberg, Marc R. Rosen, and James J. Evans
The authors present the case of a 21-year-old female with a progressive bitemporal hemianopsia. Cranial MR imaging revealed a large cystic suprasellar, retrochiasmatic lesion consistent with craniopharyngioma. The lesion was fully resected through an endoscopic endonasal transsphenoidal and transplanum approach. Closure of the resultant dural defect was performed with a bilayer fascia lata button and autologous mucoperichondrial nasoseptal flap. Each portion of this procedure was recorded and is presented in an edited high-definition format.
The video can be found here: http://youtu.be/i3-qieLlbVk.
Marc R. Rosen, Mindy R. Rabinowitz, Christopher J. Farrell, Madeleine R. Schaberg, M.P.H., and James J. Evans
Endonasal resection of olfactory groove meningiomas allows for several advantages over transcranial routes, including a direct approach to the bilateral anterior cranial base and dura mater, early tumor devascularization, and avoidance of brain retraction. Although considered minimally invasive, the endoscopicapproach to the cribriform plate typically requires resection of the superior nasal septum, resulting in a large superior septal perforation. The septal transposition technique improves preservation of sinonasal anatomy through the elimination of a septal perforation while allowing for wide exposure to the midline anterior cranial base and harvest of a nasal septal flap. Herein, the authors describe a 39-year-old female who presented with a progressively enlarging olfactory groove meningioma. An endoscopic endonasal resection with a septal transposition technique was performed. On follow-up, the nasal cavity had completely normal anatomy with preservation of the turbinatesand nasal septum.
The authors conclude that septal transposition is a useful technique that allows wide exposure of the anterior cranial base with maximal preservation of normal nasal anatomy and avoidance of a large septal perforation.
Varun R. Kshettry, Hyunwoo Do, Khaled Elshazly, Christopher J. Farrell, Gurston Nyquist, Marc Rosen, and James J. Evans
There is a paucity of literature regarding the learning curve associated with performing endoscopic endonasal cranial base surgery. The purpose of this study was to determine to what extent a learning curve might exist for endoscopic endonasal resection in cases of craniopharyngiomas.
A retrospective review was performed for all endoscopic endonasal craniopharyngioma resections performed at Thomas Jefferson University from 2005 to 2015. To assess for a learning curve effect, patients were divided into an early cohort (2005–2009, n = 20) and a late cohort (2010–2015, n = 23). Preoperative demographics, clinical presentation, imaging characteristics, extent of resection, complications, tumor control, and visual and endocrine outcomes were obtained. Categorical variables and continuous variables were compared using a 2-sided Fisher's exact test and t-test, respectively.
Only the index operation performed at the authors' institution was included. There were no statistically significant differences between early and late cohorts in terms of patient age, sex, presenting symptoms, history of surgical or radiation treatment, tumor size or consistency, hypothalamic involvement, or histological subtype. The rate of gross-total resection (GTR) increased over time from 20% to 65% (p = 0.005), and the rate of subtotal resection decreased over time from 40% to 13% (p = 0.078). Major neurological complications, including new hydrocephalus, meningitis, carotid artery injury, or stroke, occurred in 6 patients (15%) (8 complications) in the early cohort compared with only 1 (4%) in the late cohort (p = 0.037). CSF leak decreased from 40% to 4% (p = 0.007). Discharge to home increased from 64% to 95% (p = 0.024). Visual improvement was high in both cohorts (88% [early cohort] and 81% [late cohort]). Rate of postoperative panhypopituitarism and permanent diabetes insipidus both increased from 50% to 91% (p = 0.005) and 32% to 78% (p = 0.004), which correlated with a significant increase in intentional stalk sacrifice in the late cohort (from 0% to 70%, p < 0.001).
High rates of near- or total resection and visual improvement can be achieved using an endoscopic endonasal approach for craniopharyngiomas. However, the authors did find evidence for a learning curve. After 20 cases, they found a significant decrease in major neurological complications and significant increases in the rates of GTR rate and discharge to home. Although there was a large decrease in the rate of postoperative CSF leak over time, this was largely attributable to the inclusion of very early cases prior to the routine use of vascularized nasoseptal flaps. There was a significant increase in new panhypopituitarism and diabetes insipidus, which is attributable to increase rates of intentional stalk sacrifice.
Peter G. Campbell, Brian McGettigan, Adam Luginbuhl, Sanjay Yadla, Marc Rosen, and James J. Evans
The expanded endoscopic approach to craniopharyngiomas has recently been described in several small case series. The authors present their experience with this technique and review the available literature.
Between September 2006 and September 2009, 14 patients underwent a purely endoscopic, endonasal approach for resection of newly diagnosed craniopharyngiomas. These procedures represent index surgeries; no patient had undergone previous tumor resection. A retrospective review of endocrinological and ophthalmological outcomes, extent of resection, and complication prevalence was completed. Additionally, a review of the English literature was performed to evaluate outcomes of similar endoscopic techniques for resection of craniopharyngiomas.
Four patients (28.6%) underwent gross-total resection; near total resection or better was achieved in 9 patients (64.3%). All patients presented with some form of visual field or acuity deficit. Postoperatively, 12 patients (85.7%) experienced visual improvement, with 6 patients (42.9%) having complete visual recovery. One patient experienced worsening of her visual deficit. Visual acuity improved in 8 patients ((57.1%), while visual field defects improved in 11 (78.6%). The pituitary stalk was preserved in all cases. Eight (57.1%) of 14 patients experienced some form of anterior pituitary dysfunction postoperatively. Although 9 patients (64.3%) were documented to have either transient or permanent new diabetes insipidus immediately after surgery, at 1-month follow-up only 1 patient met clinical criteria. Five patients (35.7%) developed CSF leaks that were successfully treated by subsequent endoscopic revision. All CSF leaks occurred early in the series. Two patients (14.2%) were treated for presumed meningitis postoperatively.
The endoscopic endonasal approach is a minimally invasive alternative to open transcranial approaches for select craniopharyngiomas. Similar to previous transcranial series, rates of endocrinopathy and gross-total resection were dependent upon the adherence of the tumor capsule to the hypothalamus, pituitary stalk, and associated vasculature. A review of the literature suggests that the results of the current series are similar to other published series on this topic.
Peter G. Campbell, Erin Kenning, David W. Andrews, Sanjay Yadla, Marc Rosen, and James J. Evans
Using strict biochemical remission criteria, the authors assessed surgical outcomes after endoscopic transsphenoidal resection of growth hormone (GH)–secreting pituitary adenomas and identified preoperative factors that significantly influence the rate of remission.
A retrospective review of a prospectively maintained database was performed. The authors reviewed cases in which an endoscopic resection of GH-secreting pituitary adenomas was performed. The cohort consisted of 26 patients who had been followed for 3–60 months (mean 24.5 months). The thresholds of an age-appropriate, normalized insulin-like growth factor–I concentration, a nadir GH level after oral glucose load of less than 1.0 μg/l, and a random GH value of less than 2.5 μg/l were required to establish biochemical cure postoperatively.
Overall, in 57.7% of patients undergoing a purely endoscopic transsphenoidal pituitary adenectomy for acromegaly, an endocrinological cure was achieved. The mean clinical follow-up duration was 24.5 months. In patients with microadenomas (4 cases) the cure rate was 75%, whereas in patients harboring macroadenomas (22 cases) the cure rate was 54.5%. Cavernous sinus invasion (Knosp Grades 3 and 4) was associated with a significantly lower remission rate (p = 0.0068). Hardy Grade 3 and 4 tumors were also less likely to achieve biochemical cure (p = 0.013). The overall complication rate was 11.5% including 2 incidents of transient diabetes insipidus and 1 postoperative CSF leak, which were treated nonoperatively.
A purely endoscopic transsphenoidal approach to GH-secreting pituitary adenomas leads to similar outcome for noninvasive macroadenomas compared with traditional microsurgical techniques. Furthermore, this approach may often provide maximal visualization of the tumor, the pituitary gland, and the surrounding neurovascular structures.
James J. Evans, Sin-Soo Jeun, Joung H. Lee, Jyoti A. Harwalkar, Yigal Shoshan, John K. Cowell, and Mladen Golubic
Object. The neurofibromatosis Type 2 (NF2) gene is the only tumor suppressor gene that has been clearly implicated in the development of benign meningiomas. Interestingly, previous data obtained by the authors indicate that reduced NF2 protein expression seldom occurs in meningothelial meningiomas, the most common histological type of meningioma. The goal of the current study was to explore further the hypothesis of NF2 gene-independent tumorigenesis of meningothelial meningiomas.
Methods. The authors performed a mutational analysis of all 17 exons of the NF2 gene by using single-stranded conformational polymorphism (SSCP). In addition, expression levels of the NF2 protein and (µ-calpain, a protease suggested to inactivate the NF2 protein, were determined by immunoblotting analysis of 27 meningiomas (20 meningothelial and seven nonmeningothelial). Mutations of the NF2 gene were found in only one (5%) of 20 meningothelial meningiomas and three (43%) of seven nonmeningothelial tumors (Fisher's exact test, p = 0.042). The levels of NF2 protein were severely reduced in six (28.5%) of 21 meningothelial meningiomas, in contrast to six (86%) of seven nonmeningothelial meningiomas (Fisher's exact test, p = 0.023). Activation of (µ-calpain did not correlate with the status of NF2 protein expression in the meningiomas analyzed, demonstrating that (µ-calpain activation does not account for the loss of NF2 protein in meningiomas with apparently normal NF2 genes.
Conclusions. These results clearly demonstrate that NF2 gene mutations and decreased NF2 protein expression rarely occur in meningothelial meningiomas compared with other histological types of meningiomas. The clinical behavior of meningothelial meningiomas, however, is similar to that of other benign meningiomas. It is likely, therefore, that the tumorigenesis of meningothelial meningiomas is the result of deleterious alterations of genes that have final phenotypical effects similar to inactivation of the NF2 gene.
Delbert E. Evans, Philip W. Catron, James J. McDermott, Linda B. Thomas, Arthur I. Kobrine, and Edward T. Flynn
✓ To investigate possible approaches to the treatment of neural damage induced by air embolism and other forms of acute cerebral ischemia, somatosensory evoked potentials (SEP's) were measured after cerebral air embolism in the anesthetized cat. Air was introduced into the carotid artery in increments of 0.08 ml until the SEP amplitude was reduced to approximately 10% or less of baseline values. Either a saline or lidocaine infusion was begun 5 minutes after inducing cerebral ischemia. In the saline-treated group, SEP amplitude was reduced to 6.7% ± 1.6% (mean ± standard error of the mean) of baseline, with a return to 32.6% ± 4.7% of baseline over a 2-hour period. In the lidocaine-treated group, SEP amplitude was reduced to 5.9% ± 1.5%, with a return to 77.3% ± 6.2% over a 2-hour period. The results suggest that lidocaine administration facilitates the return of neural function after acute cerebral ischemia induced by air embolism.