Copeland, William R.

Spontaneous intracranial hypotension (SIH) is an uncommon headache etiology, typically attributable to an unprovoked occult spinal CSF leak. Although frequently benign, serious complications may occur, including cerebral venous thrombosis (CVT). The objective of this study was to examine a highly complicated case of CVT attributable to SIH as a lens for understanding the heterogeneous literature on this rare complication, and to provide useful, evidence-based, preliminary clinical recommendations. A 43-year-old man presented with 1 week of headache, dizziness, and nausea, which precipitously evolved to hemiplegia. CT venography confirmed CVT, and therapeutic heparin was initiated. He suffered a generalized seizure due to left parietal hemorrhage, which subsequently expanded. He developed signs of mass effect and herniation, heparin was discontinued, and he was taken to the operating room for clot evacuation and external ventricular drain placement. Intraoperatively, the dura was deflated, suggesting underlying SIH. Ventral T-1 CSF leak was identified, which failed multiple epidural blood patches and required primary repair. The patient ultimately made a complete recovery. Systematic review identified 29 publications describing 36 cases of SIH-associated CVT. Among 31 patients for whom long-term neurological outcome was reported, 25 (81%) recovered completely. Underlying coagulopathy/risk factors were identified in 11 patients (31%). CVT is a rare and potentially lethal sequela occurring in 2% of SIH cases. Awareness of the condition is poor, risking morbid complications. Evaluation and treatment should be directed toward identification and treatment of occult CSF leaks. Encouragingly, good neurological outcomes can be achieved through vigilant multidisciplinary neurosurgical and neurocritical care.

The distal dural ring (DDR) is a conserved intracranial anatomic structure marking the boundary point at which the internal carotid artery (ICA) exits the cavernous sinus (CS) and enters the subarachnoid space. Although the CS has been well described in a range of anatomic studies, to our knowledge no prior study has analyzed the histologic relationship between the ICA and DDR. Correspondingly, our objective was to assess the relationship of the DDR to the ICA and determine whether the DDR can be dissected from the ICA and thus divided, or can only be circumferentially trimmed around the artery. The authors examined ten fresh‐frozen, adult cadaveric specimens. A standard frontotemporal craniotomy, orbito‐optic osteotomy, and extradural anterior clinoidectomy was performed bilaterally. The cavernous ICA, DDR, and supraclinoid ICA were harvested as an en bloc specimen. Specimens formalin‐fixed and paraffin‐embedded prior to routine histochemical staining with hematoxylin and eosin and Masson trichrome. In all specimens, marked microscopic investment of the DDR throughout the ICA adventitia was noted. Dural collagen fibers extensively permeated the arterial layers superficial to the muscularis propria, with no evidence of a clear separation between the DDR and arterial adventitia. Histologic analysis suggests that the ICA and DDR are highly interrelated, continuous structures, and therefore attempted intraoperative dissection between these structures may carry an elevated risk of injury to the ICA. We correspondingly recommend careful circumferential trimming of the DDR in lieu of direct dissection in cases requiring mobilization of the clinoidal ICA. Clin. Anat. 30:742–746, 2017. © 2017Wiley Periodicals, Inc.

Objective: To present a single-institution experience and supportive systematic literature review examining outcomes after repeat microsurgery for recurrent vestibular schwannoma (VS) following previous gross total resection (GTR). Study Design: Retrospective review of prospectively maintained VS database. Systematic literature review. Setting: Tertiary referral center. Patients: Six proven VS recurrences after primary GTR, treated via repeat microsurgery. Intervention: Repeat microsurgery. Main Outcome Measures: Facial nerve function, extent-of-resection, time-to-repeat surgery, same versus alternate approach at repeat surgery (relative to primary operation). Results: GTR was achieved in four (67%). House–Brackmann (HB) grade I–II facial nerve function was achieved in five (87%), including one that improved from preoperative HB grade V. An alternate surgical approach was chosen in four (67%). Systematic review identified four studies documenting 50 cases with patient-specific outcomes after repeat microsurgery for recurrent VS. Our cohort had significantly longer mean time-to-repeat surgery (117 vs. 64 months, p = 0.03), was significantly less likely to have HB III–VI function postrepeat (17% vs. 68%, p = 0.04), and was significantly less likely to undergo same approach surgery (33% vs. 90%, p = 0.0002); rates of GTR were nonsignificant (67% vs. 94%, p = 0.1). Conclusion: We report a six-patient series of microsurgery for recurrent VS after GTR, and the first systematic review of this rare and challenging entity. Anecdotally, our findings suggest that an alternate surgical approach may facilitate easier access to the tumor, with less scar encountered during the approach. Our results confirm that repeat microsurgery for recurrent VS is safe and effective, even for larger tumors not typically amenable to stereotactic radiosurgery.

Objectives/HypothesisTo report two patients with a history of microvascular decompression (MVD) for hemifacial spasm who presented with Teflon granulomas (TG) mimicking cerebellopontine angle (CPA) tumors and to perform a systematic review of the English‐language literature.Study DesignCase series at a single tertiary academic referral center and systematic review.MethodsRetrospective chart review with analysis of clinical, radiological, and histopathological findings. Systematic review using PubMed, Embase, MEDLINE, and Web of Science databases.ResultsTwo patients with large skull base TGs mimicking CPA tumors clinically and radiographically were managed at the authors' institution. The first presented 4 years after MVD with asymmetrical sensorineural hearing loss, multiple progressive cranial neuropathies, and brainstem edema due to a growing TG. Reoperation with resection of the granuloma confirmed a foreign‐body reaction consisting of multinucleated giant cells containing intracytoplasmic Teflon particles. The second patient presented 11 years after MVD with asymmetrical sensorineural hearing loss and recurrent hemifacial spasm. No growth was noted over 2 years, and the patient has been managed expectantly. Only one prior case of TG after MVD for hemifacial spasm has been reported in the English literature.ConclusionsTG is a rare complication of MVD for hemifacial spasm. The diagnosis should be suspected in patients presenting with a new‐onset enhancing mass of the CPA after MVD, even when performed decades earlier. A thorough clinical and surgical history is critical toward establishing an accurate diagnosis to guide management and prevent unnecessary morbidity. Surgical intervention is not required unless progressive neurologic complications ensue.Level of Evidence4 Laryngoscope, 127:715–719, 2017

OBJECT The following study was conducted to identify risk factors for a postoperative CSF leak after vestibular schwannoma (VS) surgery. METHODS The authors reviewed a prospectively maintained database of all patients who had undergone resection of a VS at the Mayo Clinic between September 1999 and May 2013. Patients who developed a postoperative CSF leak within 30 days of surgery were compared with those who did not. Data collected included patient age, sex, body mass index (BMI), tumor size, tumor side, history of prior tumor treatment, operative time, surgical approach, and extent of resection. Both univariate and multivariate regression analyses were performed to evaluate all variables as risk factors of a postoperative CSF leak. RESULTS A total of 457 patients were included in the study, with 45 patients (9.8%) developing a postoperative CSF leak. A significant association existed between increasing BMI and a CSF leak, with those classified as overweight (BMI 25–29.9), obese (BMI 30–39.9), or morbidly obese (BMI ≥ 40) having a 2.5-, 3-, and 6-fold increased risk, respectively. Patients undergoing a translabyrinthine (TL) approach experienced a higher rate of CSF leaks (OR 2.5, 95% CI 1.3–4.6; p = 0.005), as did those who had longer operative times (OR 1.04, 95% CI 1.02–1.07; p = 0.0006). The BMI, a TL approach, and operative time remained independent risk factors on multivariate modeling. CONCLUSIONS Elevated BMI is a risk factor for the development of a postoperative CSF leak following VS surgery. Recognizing this preoperatively can allow surgeons to better counsel patients regarding the risks of surgery as well as perhaps to alter perioperative management in an attempt to decrease the likelihood of a leak. Patients undergoing a TL approach or having longer operative times are also at increased risk of developing a postoperative CSF leak.

Object The goals of this study were to report the clinical presentation, radiographic findings, operative strategy, and outcomes among patients with temporal bone encephaloceles and cerebrospinal fluid fistulas (CSFFs) and to identify clinical variables associated with surgical outcome. Methods A retrospective case series including all patients who underwent a middle fossa craniotomy or combined mastoid–middle cranial fossa repair of encephalocele and/or CSFF between 2000 and 2012 was accrued from 2 tertiary academic referral centers. Results Eighty-nine consecutive surgeries (86 patients, 59.3% women) were included. The mean age at time of surgery was 52.3 years, and the left side was affected in 53.9% of cases. The mean delay between symptom onset and diagnosis was 35.4 months, and the most common presenting symptoms were hearing loss (92.1%) and persistent ipsilateral otorrhea (73.0%). Few reported a history of intracranial infection (6.7%) or seizures (2.2%). Thirteen (14.6%) of 89 cases had a history of major head trauma, 23 (25.8%) were associated with chronic ear disease without prior operation, 17 (19.1%) occurred following tympanomastoidectomy, and 1 (1.1%) developed in a patient with a cerebral aqueduct cyst resulting in obstructive hydrocephalus. The remaining 35 cases (39.3%) were considered spontaneous. Among all patients, the mean body mass index (BMI) was 35.3 kg/m2, and 46.4% exhibited empty sella syndrome. Patients with spontaneous lesions were statistically significantly older (p = 0.007) and were more commonly female (p = 0.048) compared with those with nonspontaneous pathology. Additionally, those with spontaneous lesions had a greater BMI than those with nonspontaneous disease (p = 0.102), although this difference did not achieve statistical significance. Thirty-two surgeries (36.0%) involved a middle fossa craniotomy alone, whereas 57 (64.0%) involved a combined mastoid–middle fossa repair. There were 7 recurrences (7.9%); 2 patients with recurrence developed meningitis. The use of artificial titanium mesh was statistically associated with the development of recurrent CSFF (p = 0.004), postoperative wound infection (p = 0.039), and meningitis (p = 0.014). Also notable, 6 of the 7 cases with recurrence had evidence of intracranial hypertension. When the 11 cases that involved using titanium mesh were excluded, 96.2% of patients whose lesions were reconstructed with an autologous multilayer repair had neither recurrent CSFF nor meningitis at the last follow-up. Conclusions Patients with temporal bone encephalocele and CSFF commonly present with persistent otorrhea and conductive hearing loss mimicking chronic middle ear disease, which likely contributes to a delay in diagnosis. There is a high prevalence of obesity among this patient population, which may play a role in the pathogenesis of primary and recurrent disease. A middle fossa craniotomy or a combined mastoid–middle fossa approach incorporating a multilayer autologous tissue technique is a safe and reliable method of repair that may be particularly useful for large or multifocal defects. Defect reconstruction using artificial titanium mesh should generally be avoided given increased risks of recurrence and postoperative meningitis.