Christopher S. Graffeo, Kathryn M. Van Abel, Jonathan M. Morris, Matthew L. Carlson, Jamie J. Van Gompel, Eric J. Moore, Daniel L. Price, Jan L. Kasperbauer, Jeffrey R. Janus, Kerry D. Olsen and Michael J. Link
Vagus nerve and sympathetic chain cervical schwannomas (VNCSs and SCCSs) are benign nerve sheath tumors that arise in the head and neck. Despite similar presentations that make accurate preoperative diagnosis more difficult, the potential for morbidity following resection is significantly higher for patients with VNCS. Therefore, the authors analyzed a retrospective case series and performed a comparative analysis of the literature to establish diagnostic criteria to facilitate more accurate preoperative diagnoses.
The authors conducted a blinded review of imaging studies from retrospectively collected, operatively confirmed cases of VNCS and SCCS. They also performed a systematic review of published series that reported patient-specific preoperative imaging findings in VNCS or SCCS.
Nine patients with VNCS and 11 with SCCS were identified. In the study cohort, splaying of the internal carotid artery (ICA) and internal jugular vein (IJV) did not significantly predict the nerve of origin (p = 0.06); however, medial and lateral ICA displacement were significantly associated with VNCS and SCCS, respectively (p = 0.01 and p = 0.003, respectively). Multivariate analysis demonstrated that ICA and IJV splaying with medial ICA displacement carried an 86% probability of VNCS (p = 0.001), while the absence of splaying with lateral ICA displacement carried a 91% probability of SCCS (p = 0.006). The presence of vocal cord symptoms or peripheral enhancement significantly augmented the predictive probability of VNCS, as did Horner's syndrome or homogeneous enhancement for SCCS.
A review of the literature produced 25 publications that incorporated a total of 106 patients, including the present series. Splaying of the ICA and IJV was significantly, but not uniquely, associated with VNCS (p < 0.0001); multivariate analysis demonstrated that ICA and IJV splaying with medial ICA displacement carries a 75% probability of VNCS (p < 0.0001), while the absence of such splaying with lateral ICA displacement carries an 87% probability of SCCS (p = 0.0003).
ICA and IJV splaying frequently predicts VNCS; however, this finding is also commonly observed in SCCS and, among the 9 cases in the present study, was observed more often than previously reported. When congruent with splaying, medial or lateral ICA displacement significantly enhances the reliability of preoperative predictions, empowering more accurate prognostication.
Takashi Tsuboi, Janine Lemos Melo Lobo Jofili Lopes, Kathryn Moore, Bhavana Patel, Joseph Legacy, Adrianna M. Ratajska, Dawn Bowers, Robert S. Eisinger, Leonardo Almeida, Kelly D. Foote, Michael S. Okun and Adolfo Ramirez-Zamora
Few studies have reported long-term outcomes of globus pallidus internus (GPi) deep brain stimulation (DBS) in Parkinson’s disease (PD). The authors aimed to investigate long-term outcomes of bilateral GPi DBS for 5 years and beyond for PD patients.
The authors retrospectively analyzed the clinical outcomes in 65 PD patients treated with bilateral GPi DBS at a single center. The outcome measures of motor symptoms and health-related quality of life (HRQoL) included the Unified Parkinson’s Disease Rating Scale (UPDRS) and the Parkinson’s Disease Questionnaire (PDQ-39). Scores at baseline were compared with those at 1, 3, 5, and 6–8 years after implantation using Wilcoxon signed-rank tests with α correction.
GPi DBS significantly improved the off-medication UPDRS III total scores, UPDRS IV, and dyskinesia score at 1 year when compared with baseline (all p < 0.001). The off- and on-medication tremor scores, UPDRS IV, and dyskinesia scores showed moderate and sustained improvement (the ranges of the mean percentage improvement at each time point were 61%–75%, 30%–80%, 29%–40%, and 40%–65%, respectively) despite lacking statistical significance at long-term follow-up with diminishing sample sizes. The off-medication UPDRS III total scores did not show significant improvement at 5 years or later, primarily because of worsening in rigidity, akinesia, speech, gait, and postural stability scores. The on-medication UPDRS III total scores also worsened over time, with a significant worsening at 6–8 years when compared with baseline (p = 0.008). The HRQoL analyses based on the PDQ-39 revealed significant improvement in the activities of daily living and discomfort domains at 1 year (p = 0.003 and 0.006, respectively); however, all the domains showed gradual worsening at the later time points without reaching statistical significance. At 3 years, the communication domain showed significant worsening compared with baseline scores (p = 0.002).
GPi DBS in PD patients in this single-center cohort was associated with sustained long-term benefits in the off- and on-medication tremor score and motor complications. HRQoL and the cardinal motor symptoms other than tremor may worsen gradually in the long term. When counseling patients, it is important to recognize that benefits in tremor and dyskinesia are expected to be most persistent following bilateral GPi DBS implantation.
Kathryn M. Van Abel, Grant W. Mallory, Jan L. Kasperbauer, M.D., Eric J. Moore, Daniel L. Price, Erin K. O’Brien, Kerry D. Olsen, William E. Krauss, Michelle J. Clarke, Mark E. Jentoft and Jamie J. Van Gompel
Swallowing dysfunction is common following transoral (TO) odontoidectomy. Preliminary experience with newer endoscopic transnasal (TN) approaches suggests that dysphagia may be reduced with this alternative. However, the reasons for this are unclear. The authors hypothesized that the TN approach results in less disruption of the pharyngeal plexus and anatomical structures associated with swallowing. The authors investigate the histological and gross surgical anatomical relationship between pharyngeal plexus innervation of the upper aerodigestive tract and the surgical approaches used (TN and TO). They also review the TN literature to evaluate swallowing outcomes following this approach.
Seven cadaveric specimens were used for histological (n = 3) and gross anatomical (n = 4) examination of the pharyngeal plexus with the TO and TN surgical approaches. Particular attention was given to identifying the location of cranial nerves (CNs) IX and X and the sympathetic chain and their contributions to the pharyngeal plexus. S100 staining was performed to assess for the presence of neural tissue in proximity to the midline, and fiber density counts were performed within 1 cm of midline. The relationship between the pharyngeal plexus, clivus, and upper cervical spine (C1-3) was defined.
Histological analysis revealed the presence of pharyngeal plexus fibers in the midline and a significant reduction in paramedian fiber density from C-2 to the lower clivus (p < 0.001). None of these paramedian fibers, however, could be visualized with gross inspection or layer-by-layer dissection. Laterally based primary pharyngeal plexus nerves were identified by tracing their origins from CNs IX and X and the sympathetic chain at the skull base and following them to the pharyngeal musculature. In addition, the authors found 15 studies presenting 52 patients undergoing TN odontoidectomy. Of these patients, only 48 had been swallowing preoperatively. When looking only at this population, 83% (40 of 48) were swallowing by Day 3 and 92% (44 of 48) were swallowing by Day 7.
Despite the midline approach, both TO and TN approaches may injure a portion of the pharyngeal plexus. By limiting the TN incision to above the palatal plane, the surgeon avoids the high-density neural plexus found in the oropharyngeal wall and limits injury to oropharyngeal musculature involved in swallowing. This may explain the decreased incidence of postoperative dysphagia seen in TN approaches. However, further clinical investigation is warranted.