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Dive into the research topics where Volker K.H. Sonntag is active.

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Featured researches published by Volker K.H. Sonntag.


Neurosurgery | 1998

Posterior C1-C2 transarticular screw fixation for atlantoaxial arthrodesis

Curtis A. Dickman; Volker K.H. Sonntag

OBJECTIVEnTo assess the outcomes associated with C1-C2 transarticular screw fixation.nnnMETHODSnThe clinical outcomes of 121 patients treated with posterior C1-C2 transarticular screws and wired posterior C1-C2 autologous bone struts were evaluated prospectively. Atlantoaxial instability was caused by rheumatoid arthritis in 48 patients, C1 or C2 fractures in 45, transverse ligament disruption in 11, os odontoideum in 9, tumors in 6, and infection in 2.nnnRESULTSnAltogether, 226 screws were placed under lateral fluoroscopic guidance. Bilateral C1-C2 screws were placed in 105 patients; each of 16 patients had only one screw placed because of an anomalous vertebral artery (n = 13) or other pathological abnormality. Postoperatively, each patient underwent radiography and computed tomography to assess the position of the screw and healing. Most screws (221 screws, 98%) were positioned satisfactorily. Five screws were malpositioned (2%), but none were associated with clinical sequelae. Four malpositioned screws were reoperated on (one was repositioned, and three were removed). No patients had neurological complications, strokes, or transient ischemic attacks. Long-term follow-up (mean, 22 mo) of 114 patients demonstrated a 98% fusion rate. Two nonunions (2%) required occipitocervical fixation. In comparison, our C1-C2 fixations with wires and autograft (n = 74) had an 86% union rate.nnnCONCLUSIONnRigidly fixating C1-C2 instability with transarticular screws was associated with a significantly higher fusion rate than that achieved using wired grafts alone. The risk of screw malpositioning and catastrophic vascular or neural injury is small and can be minimized by assessing the position of the foramen transversaria on preoperative computed tomographic scans and by using intraoperative fluoroscopy and frameless stereotaxy to guide the screw trajectory.


Neurosurgery | 1985

Axis fractures: a comprehensive review of management and treatment in 107 cases

Mark N. Hadley; Carol M. Browner; Volker K.H. Sonntag

The combination of movement, location, and anatomy of the axis predisposes it to multiple and varied fracture/dislocations distinct from other vertebrae. We examine all forms of axis fractures and address the appropriate treatment for each specific fracture type. In a retrospective review of 625 cervical spine fractures during an 8-year period, we found 107 axis fractures. There were 25 hangmans fractures (23%), 59 odontoid fractures (55%), and 23 miscellaneous fractures (22%). Each case was characterized by age, sex, the presence of associated injuries, presenting symptoms and findings, initial treatment, and results of that treatment. Excluding 6 early deaths, 90 of 101 patients were located for a median follow-up of 3.2 years. We found that 17% of cervical fractures involve the axis. Axis fractures have a high association with head and other cervical spine injuries, 40% and 18%, respectively. Few neurological deficits result from a fracture of the 2nd cervical vertebra. Hangmans fractures are effectively treated with external stabilization, preferably with a halo vest. We noted a shorter period of treatment using the halo vest as compared to the SOMI brace. Nonunion occurred in 26% of odontoid Type II fractures, but occurred in 67% of those with dens displacement of 6 mm or greater, regardless of age or direction of dislocation. We recommend early surgical therapy for this subgroup. There is no correlation between age and the rate of nonunion. In patients with odontoid Type II fractures with dens displacement of 0 to 5 mm, fusion occurs with external stabilization alone. Odontoid Type III fractures are one-half as common as Type II fractures, and all heal well with external stabilization. Twenty-two per cent of acute axis fractures are not hangmans or odontoid fractures. Miscellaneous fractures of the axis generally do well with external stabilization and immobilization.


Neurosurgery | 1989

The infant whiplash-shake injury syndrome: a clinical and pathological study.

Mark N. Hadley; Volker K.H. Sonntag; Harold L. Rekate; Alan R. Murphy

The cases of 13 infants (median age, 3 months) who sustained nonaccidental trauma were reviewed. All presented with profound neurological impairment, seizures, retinal hemorrhages, and intracranial subarachnoid and/or subdural hemorrhages. Of 8 infants who died, autopsy was performed on 6. No patient had a skull fracture, and only one had an extracalvarial contusion. Five of the 6 patients on whom autopsy was performed had injuries at the cervicomedullary junction consisting of sub- or epidural hematomas of the cervical spinal cord with proximal spinal cord contusions. The authors conclude that direct cranial trauma is not an essential element of the injury mechanism in young patients who sustain severe whiplash-shake injuries. In addition to the classic injuries reported to occur with the shaken-baby syndrome, hemorrhages and contusions of the high cervical spinal cord may contribute to morbidity and mortality.


Neurosurgery | 1992

Outcome analysis in 654 surgically treated lumbar disc herniations.

Conrad T. E. Pappas; Timothy Harrington; Volker K.H. Sonntag

This article reports the outcomes of 654 consecutive patients treated during a 4.5-year period. Patients had a microdiscectomy, a laminectomy plus microdiscectomy, or a decompressive laminectomy with a microdiscectomy. The causes of ruptured discs were lifting (31.4%), falls (10.2%), and sports (10.0%). Almost all patients had complained of leg pain (99%), and 79% had radicular pain in a dermatomal distribution. Thirty-three percent of the patients had been involved in industrial accidents, and 6% had legal claims pending during the surgical period. Almost 11% of the patients had complications, and there was one death caused by abdominal arterial bleeding. Patients were also rated according to the Prolo Functional-Economic Outcome Rating Scale to improve the ability to compare series in the future. Almost 80% of the patients had good outcomes as defined by scores on this scale of 8 (16.2%), 9 (33.2%), and 10 (26.9%). Several conclusions can be drawn from the results of this series: 1) most patients had good outcomes; 2) patients with nonindustrial injuries had better outcomes than did patients with industrial injuries; 3) professionals with legal concerns and laborers with industrial insurance had good outcomes; and 4) the Functional-Economic Outcome Rating Scale appears to be a useful tool for comparing different procedures more objectively and for comparing the outcomes across series.


Neurosurgery | 1991

Traumatic atlantooccipital dislocation with survival.

Stephen M. Papadopoulos; Curtis A. Dickman; Volker K.H. Sonntag; Harold L. Rekate; Robert F. Spetzler

Survival after traumatic atlantooccipital dislocation is rare. Only long-term survivors have been reported in the literature; however, improved prehospital care is likely responsible for the increase in the number of these patients seen at neurotrauma centers over the last decade. Associated severe and persistent neurological deficits are common in the few survivors. We report the case of a 10-year-old boy with traumatic atlantooccipital dislocation and a severe neurological injury. Low-field magnetic resonance imaging provided the additional diagnosis of an associated cervicomedullary epidural hematoma. The patient underwent emergency operative evacuation of the hematoma and an occipital-cervical fusion with internal fixation. He had a remarkable recovery in neurological function and achieved stable bony fusion 3 months postoperatively. With early recognition of this entity, improved neuroradiological imaging techniques, and aggressive treatment, patients may survive with significant neurological recovery.


Neurosurgery | 1992

Facet fracture-dislocation injuries of the cervical spine.

Mark N. Hadley; Brian C. Fitzpatrick; Volker K.H. Sonntag; Carol M. Browner

Sixty-eight patients with acute traumatic cervical facet fracture-dislocation injuries are presented. These patients represented 6.7% of all cervical spine fractures identified over a 12-year period. Thirty-one patients had unilateral facet injuries and 37 had bilateral facet injuries. Neurological morbidity was 90% and was most severe among bilateral facet injury patients (84% complete injuries). Spinal shock was identified in 13 patients and was a poor prognostic indicator for the subsequent recovery of associated neurological deficits. Closed reduction was attempted in 66 of 68 patients and was successful in 58% of the patients. Seven patients deteriorated. Open reduction-internal fixation was successful in 83% of 24 patients with a 4% morbidity. Seventy-eight percent of patients improved with rapid closed reduction, and 60% improved with open reduction-internal fixation; however, only 10 patients of the entire 68 made significant neurological recoveries. In these 10 patients, the timing of decompression-realignment appeared to be more important than the means of reduction.


Neurosurgery | 1988

New subtype of acute odontoid fractures (type IIA).

Mark N. Hadley; Carol M. Browner; Shih Sing Liu; Volker K.H. Sonntag

A new subtype of axis fracture, thought to be a variant of the Type II odontoid fracture, is described. High resolution, thin section computed tomography can assist in the identification of comminuted fractures at the base of the dens with associated free fracture fragments. Because these injuries are markedly unstable and cannot be suitably realigned and reduced by external means, early surgical therapy should be considered.


Neurosurgery | 2001

Spontaneous intracranial hypotension mimicking aneurysmal subarachnoid hemorrhage.

Wouter I. Schievink; Eelco F. M. Wijdicks; Fredric B. Meyer; Volker K.H. Sonntag

OBJECTIVEAn excruciating headache of instantaneous onset is known as a thunderclap headache. A subarachnoid hemorrhage is the prototypical cause, but other serious disorders may also present with a thunderclap headache, including cerebral venous sinus thrombosis, carotid artery dissection, and pituitary apoplexy. We report a group of patients with thunderclap headaches as the initial manifestation of spontaneous intracranial hypotension caused by a spinal cerebrospinal fluid leak. METHODSAmong 28 patients with spontaneous intracranial hypotension due to a documented spinal cerebrospinal fluid leak, four (14%) initially experienced an excruciating headaches of instantaneous onset. RESULTSThe mean age of the four patients (two men and two women) was 35 years (range, 24–45 yr). Nuchal rigidity was present in the three patients who sought early medical attention, and they underwent emergency computed tomographic scanning, lumbar puncture, and cerebral angiography to rule out an aneurysmal subarachnoid hemorrhage. The delay between the onset of headache and diagnosis of intracranial hypotension ranged from 4 days to 5 weeks. A fourth patient did not seek medical attention until 1 month after the ictus. CONCLUSIONSpontaneous intracranial hypotension should be included in the differential diagnosis of thunderclap headache, even when meningismus is present.


Neurosurgery | 1981

Management of bilateral locked facets of the cervical spine.

Volker K.H. Sonntag

The management of 15 cases of bilateral locked facets of the cervical spine is reviewed. The C-6, C-7 interspace was the most common interspace involved. There were 4 females and 11 males who were 16 to 63 years old (average, 26 years). Thirteen patients had a complete spinal cord lesion with loss of function below the level of the locked facets. Two had intact dorsal column function. One patient had an ascending spinal cord deficit, which did not change after open reduction. The remainder had no change in spinal cord function after reduction. However, after reduction, 1 patient had a transient root deficit and 2 patients improved in the function of the involved roots. Closed reduction was accomplished by (a) skeletal traction and weight application, (b) manual reduction under sedatives, or (c) manual reduction under general anesthesia. Five patients required open reduction. The failure of closed reduction was attributed to accompanying fractures of one of the facets in 2 cases, increasing neurological deficits during traction in 2 cases, and associated higher cervical fractures in 1 case. Internal stabilization with wire and bone or external stabilization with a halo vest or a brace was used. Twelve patients were followed for 1 1/2 to 7 years (average, 2.7 years). Stabilization after reduction was successful irrespective of the methods used. The various methods of reduction and stabilization are reviewed and discussed.


Neurosurgery | 1985

Anatomical study of the superficial temporal artery.

Stephen R. Marano; Donald W. Fischer; Casey Gaines; Volker K.H. Sonntag

Fifty consecutive human autopsy specimens were studied to determine the suitability of the superficial temporal artery (STA) for use in microvascular anastomoses. Ten variations of the STA were found. The STA at the zygoma averaged 2.2 mm in outside diameter. The STA averaged 31.7 mm from the zygoma to its bifurcation, where the average outside diameter was 1.9 mm. Eight per cent of the specimens had no bifurcation, and 92% had at least one branch in a frontal or parietal distribution that was greater than or equal to 1 mm. A suitable frontal branch (i.e., greater than or equal to 1 mm in diameter and greater than or equal to 70 mm in length) was found in 90% of the specimens, and a suitable parietal branch was found in 71%. Six specimens (12%) had an additional branch, all of which were of suitable length and diameter. Eight per cent of the specimens lacked a vessel suitable for microvascular anastomosis.

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Curtis A. Dickman

Barrow Neurological Institute

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Mark N. Hadley

Barrow Neurological Institute

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Neil R. Crawford

St. Joseph's Hospital and Medical Center

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Robert F. Spetzler

Barrow Neurological Institute

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Carol M. Browner

Barrow Neurological Institute

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A. Giancarlo Vishteh

Barrow Neurological Institute

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C. A. Dickman

Barrow Neurological Institute

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Nicholas Theodore

St. Joseph's Hospital and Medical Center

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Paul J. Apostolides

Barrow Neurological Institute

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