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Sebastian Siller, Rami Kasem, Thomas-Nikolaus Witt, Joerg-Christian Tonn and Stefan Zausinger

OBJECTIVE

Various neurological diseases are known to cause progressive painless paresis of the upper limbs. In this study the authors describe the previously unspecified syndrome of compression-induced painless cervical radiculopathy with predominant motor deficit and muscular atrophy, and highlight the clinical and radiological characteristics and outcomes after surgery for this rare syndrome, along with its neurological differential diagnoses.

METHODS

Medical records of 788 patients undergoing surgical decompression due to degenerative cervical spine diseases between 2005 and 2014 were assessed. Among those patients, 31 (3.9%, male to female ratio 4.8 to 1, mean age 60 years) presented with painless compressive cervical motor radiculopathy due to neuroforaminal stenosis without signs of myelopathy; long-term evaluation was available in 23 patients with 49 symptomatic foraminal stenoses. Clinical, imaging, and operative findings as well as the long-term course of paresis and quality of life were analyzed.

RESULTS

Presenting symptoms (mean duration 13.3 months) included a defining progressive flaccid radicular paresis (median grade 3/5) without any history of radiating pain (100%) and a concomitant muscular atrophy (78%); 83% of the patients were smokers and 17% patients had diabetes. Imaging revealed a predominantly anterior nerve root compression at the neuroforaminal entrance in 98% of stenoses. Thirty stenoses (11 patients) were initially decompressed via an anterior surgical approach and 19 stenoses (12 patients) via a posterior surgical approach. Overall reoperation rate due to new or recurrent stenoses was 22%, with time to reoperation shorter in smokers (p = 0.033). Independently of the surgical procedure chosen, long-term follow-up (mean 3.9 years) revealed a stable or improved paresis in 87% of the patients (median grade 4/5) and an excellent general performance and quality of life.

CONCLUSIONS

Painless cervical motor radiculopathy predominantly occurs due to focal compression of the anterior nerve root at the neuroforaminal entrance. Surgical decompression is effective in stabilizing or improving motor function with a resulting favorable long-term outcome.

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Sebastian Siller, Andrea Szelényi, Lisa Herlitz, Joerg Christian Tonn and Stefan Zausinger

OBJECTIVE

Spinal cord hemangioblastomas are rare benign tumors developing either sporadically or as part of von Hippel-Lindau (VHL) disease. Generally, resection is the treatment of choice. However, the significance of intraoperative neurophysiological monitoring (IONM) for resection and postoperative outcome is still controversial. The authors analyzed the surgical and clinical courses of patients who had undergone resection of spinal cord hemangioblastoma, with special attention to preoperative imaging, the use of IONM, and short- and long-term outcomes.

METHODS

A series of 24 patients (male/female 1:1, lesion sporadic/associated with VHL 2.4:1) who had undergone 26 operations for the resection of 27 spinal cord hemangioblastomas was analyzed. All patients had undergone pre- and postoperative contrast-enhanced MRI. In all cases, microsurgical tumor removal had been performed under continuous IONM of both somatosensory and transcranial motor evoked potentials as well as electromyographic recording. Clinical characteristics, imaging findings, and operative records were retrospectively analyzed. Outcome parameters included short- and long-term status as regards sensorimotor deficits and a questionnaire on general performance, patient satisfaction, and Oswestry Disability Index (ODI) at the end of the follow-up period. The impact of IONM findings on postoperative deficits and outcome parameters as well as risk factors affecting functional prognosis was statistically assessed.

RESULTS

Preoperative symptoms (mean duration 16.2 ± 22.0 months) included sensory changes (100.0%), pain (66.7%), spinal ataxia (66.7%), motor deficit (41.7%), and bladder/bowel dysfunction (12.5%). Average age at the first operation was 36.8 ± 12.8 years. Most tumors (21 intramedullary, 6 intra- and/or extramedullary) were located dorsally (92.6%) and cervically (77.8%) and were accompanied by peritumoral edema and/or syringomyelia (81.5%). Tumor resection was achieved via laminectomy for 15 tumors, hemilaminectomy for 5, laminoplasty for 6, and interlaminar approach for 1. Gross-total resection was accomplished for 26 tumors (96.3%) with no local tumor recurrence during follow-up. Intraoperative neurophysiological monitoring was nonpathological in 11 operations (42.3%) and pathological in 15 (57.7%). Patients with nonpathological IONM had significantly fewer new sensorimotor deficits (p = 0.005). Long-term follow-up evaluation (mean 7.9 ± 4.0 years postoperatively, 7 patients lost to follow-up) revealed a stable or improved McCormick myelopathy grade in 88.2% of the patients, and 88.2% reported a stable or improved overall outcome according to Odom's criteria. Long-term general performance was excellent with 88.2% having a WHO/Eastern Cooperative Oncology Group (ECOG) Performance Status grade ≤ 1, 76.5% a Karnofsky Performance Scale score ≥ 80, and 70.6% a Barthel Index (BI) of 100. The mean ODI (11.4% ± 12.5%) indicated only minimal disability. There was a significant correlation between pathological IONM findings and a worse long-term status according to the BI and ODI (p = 0.011 and 0.024, respectively). Additionally, VHL disease was a risk factor affecting functional prognosis (p = 0.044).

CONCLUSIONS

Microsurgical removal of spinal cord hemangioblastomas with IONM facilitates a satisfying long-term outcome for patients. Nonpathological IONM findings are associated with a lower risk of new sensorimotor deficits and correlate with a better overall long-term outcome. von Hippel–Lindau disease is a risk factor for a worse long-term prognosis.

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Sebastian Siller, Caroline Zoellner, Manuel Fuetsch, Raimund Trabold, Joerg-Christian Tonn and Stefan Zausinger

OBJECTIVE

Since the 1970s, the operating microscope (OM) has been a standard for visualization and illumination of the surgical field in spinal microsurgery. However, due to its limitations (e.g., size, costliness, and the limited movability of the binocular lenses, in addition to discomfort experienced by surgeons due to the posture required), there are efforts to replace the OM with exoscopic video telescopes. The authors evaluated the feasibility of a new 3D exoscope as an alternative to the OM in spine surgeries.

METHODS

Patients with degenerative pathologies scheduled for single-level lumbar or cervical spinal surgery with use of a high-definition 3D exoscope were enrolled in a prospective cohort study between January 2019 and September 2019. Age-, sex-, body mass index–, and procedure-matched patients surgically treated with the assistance of the OM served as the control group. Operative baseline and postoperative outcome parameters were assessed. Periprocedural handling, visualization, and illumination by the exoscope, as well as surgeons’ comfort level in terms of posture, were scored using a questionnaire.

RESULTS

A 3D exoscope was used in 40 patients undergoing lumbar posterior decompression (LPD) and 20 patients undergoing anterior cervical discectomy and fusion (ACDF); an equal number of controls in whom an OM was used were studied. Compared with controls, there were no significant differences for mean operative time (ACDF: 132 vs 116 minutes; LPD: 112 vs 113 minutes) and blood loss (ACDF: 97 vs 93 ml; LPD: 109 vs 55 ml) as well as postoperative improvement of symptoms (ACDF/Neck Disability Index: p = 0.43; LPD/Oswestry Disability Index: p = 0.76). No intraoperative complications occurred in either group. According to the attending surgeon, the intraoperative handling of instruments was rated to be comparable to that of the OM, while the comfort level of the surgeon’s posture intraoperatively (especially during “undercutting” procedures) was rated as superior. In cases of ACDF procedures and long approaches, depth perception, image quality, and illumination were rated as inferior when compared with the OM. By contrast, for operating room nursing staff participating in 3D exoscope procedures, the visualization of intraoperative process flow and surgical situs was rated to be superior to the OM, especially for ACDF procedures.

CONCLUSIONS

A 3D exoscope seems to be a safe alternative for common spinal procedures with the unique advantage of excellent comfort for the surgical team, but the drawback is the still slightly inferior visualization/illumination quality compared with the OM.

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Alexander Muacevic, Michael Staehler, Christian Drexler, Berndt Wowra, Maximilian Reiser and Joerg-Christian Tonn

Object

The authors describe the technical application of the Xsight Spine Tracking System, data pertaining to accuracy obtained during phantom testing, and the initial clinical feasibility of using this fiducial-free alignment system with the CyberKnife in spinal radiosurgery.

Methods

The Xsight integrates with the CyberKnife radiosurgery system to eliminate the need for implantation of radiographic markers or fiducials prior to spinal radiosurgery. It locates and tracks spinal lesions relative to spinal osseous landmarks. The authors performed 10 end-to-end tests of accuracy using an anthropomorphic head and cervical spine phantom. Xsight was also used in the treatment of 50 spinal lesions in 42 patients. Dose planning was based on 1.5-mm-thick computed tomography slices in which an inverse treatment planning technique was used.

All lesions could be treated using the fiducial-free tracking procedure. Phantom tests produced an overall mean targeting error of 0.52 ± 0.22 mm. The setup time for patient alignment averaged 6 minutes (range 2–45 minutes). The treatment doses varied from 12 to 25 Gy to the median prescription isodose of 65% (40 to 70%). The tumor volume ranged between 1.3 and 152.8 cm3The mean spinal cord volume receiving greater than 8 Gy was 0.69 ± 0.35 cm3No short-term adverse events were noted during the 1- to 7-month follow-up period. Axial and radicular pain was relieved in 14 of 15 patients treated for pain.

Conclusions

Fiducial-free tracking is a feasible, accurate, and reliable tool for radiosurgery of the entire spine. By eliminating the need for fiducial implantation, the Xsight system offers patients noninvasive radiosurgical intervention for intra- and paraspinal tumors.

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Juergen Lutz, Niklas Thon, Robert Stahl, Nina Lummel, Joerg-Christian Tonn, Jennifer Linn and Jan-Hinnerk Mehrkens

OBJECT

In this prospective study diffusion tensor imaging (DTI) was used to evaluate the influence of clinical and anatomical parameters on structural alterations within the fifth cranial nerve in patients with trigeminal neuralgia (TN) due to neurovascular compression.

METHODS

Overall, 81 patients (40 men and 41 women; mean age 60 ± 5 years) with typical TN were included who underwent microsurgical decompression. Preoperative 3.0-T high-resolution MRI and DTI were analyzed in a blinded fashion. The respective fractional anisotropy (FA) and apparent diffusion coefficient values were compared with the clinical, imaging, and intraoperative data. This study was approved by the institutional review board, and written informed consent was obtained from all patients.

RESULTS

DTI analyses revealed significantly lower FA values within the vulnerable zone of the affected trigeminal nerve compared with the contralateral side (p = 0.05). The DTI analyses also included 3 patients without clear evidence of neurovascular conflict on preoperative MRI. No differences were seen between arterial and venous compression. Lower FA values were found 5 months after symptom onset; however, no correlation was found with the duration of symptoms or severity of compression.

CONCLUSIONS

DTI analysis allows the quantification of structural alterations, even in those patients without any discernible neurovascular contact on MRI. Moreover, our findings support the hypothesis that both the arteries and veins can cause structural alterations that lead to TN. These aspects can be useful for making treatment decisions.

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Josef Ilmberger, Maximilian Ruge, Friedrich-Wilhelm Kreth, Josef Briegel, Hans-Juergen Reulen and Joerg-Christian Tonn

Object

This prospective longitudinally designed study was conducted to evaluate language functions pre- and postoperatively in patients who underwent microsurgical treatment of tumors in close proximity to or within language areas and to detect those patients at risk for a postoperative aphasic disturbance.

Methods

Between 1991 and 2005, 153 awake craniotomies with subsequent cortical mapping of language functions were performed in 149 patients. Language functions were assessed using a standardized test battery. Risk factors were obtained from multivariate logistic regression models.

Results

Language mapping was able to be performed in all patients, and complete tumor resection was achieved in 48.4%. Within 21 days after surgery a new language deficit (aphasic disturbance) was observed in 41 (32%) of the 128 cases without preoperative deficits. There were a total of 60 cases involving postoperative aphasic disturbances, including cases both with and without preoperative disturbances. Risk factors for postoperative aphasic disturbance were preoperative aphasia (p < 0.0002), intraoperative complications (p < 0.02), language-positive sites within the tumor (p < 0.001), and nonfrontal lesion location (p < 0.001). In patients without a preoperative deficit, a normal (yet submaximal) naming performance was a powerful predictor for an early postoperative aphasic disturbance (p < 0.0003). Seven months after treatment 10.9% of the 128 cases without preoperative aphasic disturbances continued to demonstrate new postoperative language disturbances. A total of 17.6% of all cases demonstrated new postoperative language disturbances after 7 months. Risk factors for persistent aphasic disturbance were increased age (> 40 years, p < 0.02) and preoperative aphasia (p < 0.001).

Conclusions

Every attempt should be undertaken to preserve language-relevant areas intraoperatively, even when they are located within the tumor. New postoperative deficits resolve in the majority of patients, which may be a result of cortical mapping as well as functional reorganization.