Howard B. Cotler

Acute spinal cord injury : a study using physical examination and magnetic resonance imaging

Magnetic resonance imaging (MRI) was performed on 37 patients with acute spinal injury using T1− and T2-weighted images. Three different types of MRI signal patterns were detected in association with these spinal cord injuries. A classification was developed using these three patterns. Type I, seen in ten (27.0%) of the patients, demonstrated a decreased signal intensity consistent with acute intraspinal hemorrhage. Type II, seen in 16 (43.2%) of the patients, demonstrated a bright signal intensity consistent with acute cord edema. Type III, seen in three (8.1%) of the patients, demonstrated a mixed signal of hypointensity centrally and hyperintensity peripherally consistent with contusion. The remaining eight patients had normal cords by MRI. All 37 patients had an admitting neurologic assessment and classification of their spinal injury according to the Frankel classification and the Trauma Motor Index (TMI). At an average of 12.1 months postinjury, their neurologic function was reassessed. Patients with Type I patterns showed no improvement in their Frankel classification and minimal improvement in their TMI, 32.1 to 42.4. In comparison, all of the Type II and III patterns improved at least one Frankel classification. The Type II TMI increased from 70.8 to 91.9 and Type III from 37.3 to 75.7. This preliminary report indicates a distinct correlation between the pattern of spinal cord injury as identified by MRI and neurologic recovery. It appears that the ability of MRI to aid in examination of the condition of the spinal cord will offer a means of predicting neurologic recovery following acute spinal cord injury.

Postoperative infections in spinal implants : classification and analysis : a multicenter study

A multicenter study was undertaken to analyze postoperative wound infections after posterior spinal instrumentation and fusion. The infection rate of these procedures has been documented in multiple reports. From these results, a classification scheme was developed that can guide therapy and determine the populations at risk. The patients were categorized according to two parameters, the first being the severity or type of infection, and the second being the host response or physiologic classification of the patient. This classification scheme is based on the clinical staging system for adult osteomyelitis developed by Cierny. The severity of infection is divided into three groups. Group 1 is a single-organism infection, either superficial or deep. Group 2 is a multiple-organism, deep infection. Group 3 is multiple organisms with myonecrosis. The host response, likewise, is divided into three classes. Class A is a host with normal systemic defenses, metabolic capabilities, and vascularity. Class B patients demonstrate local or multiple systemic diseases, including cigarette smoking. Class C requires an immunocompromised or severely malnourished host. Our data have demonstrated that single organisms, Group 1, generally can be dealt with by single irrigation and debridement, and closure over suction drainage tubes without the use of an inflow-irrigation system. The Group 2 patients, with multiple organisms and deep infection, required an average of three irrigation debridements. They have a higher percentage of successful closures with closed inflow-outflow suction irrigation systems when compared to simple suction drainage systems without constant inflow irrigation. Multiple- organism infections with myonecrosis, Group 3, are ex@ceedingly difficult to manage, and portend a poor outcome. Patients without normal host defenses, Classes B and C, are at high risk for developing postop@erative wound infection. Specifically, this study demon@strated that cigarette smoking may be a significant risk factor.

Posterior fixation of thoracic and lumbar spine fractures using DC plates and pedicle screws.

A prospective investigation of internal fixation of acute thoracic and lumbar spine fractures using pedicle screws and dynamic compression plates was performed. This article details the results of 23 patients who were followed for an average of 20 months. The indications for the procedure were an unstable fracture-dislocation below the eighth thoracic vertebra or low lumbar fractures that would be difficult to treat with conventional spinal implants. The patients were divided into three groups based on the fracture pattern and the level of the fracture. Group I consisted of fracture—dislocation injuries at the thoracic level and thoracolumbar junction. Group II patients sustained lumbar fracture—dislocations, and Group III contained lumbar burst fractures. Sagittal and coronal angles as well as anterior and posterior vertebral body height were measured at the injury level preoperatively, postoperatively, and at 3-month intervals. Statistical analysis of these angles demonstrated that Group I and III patients had significant correction of their relative kyphotic deformity after surgery; however, there were no differences in kyphotic angle at the 3-month interval. Despite this eventual return to preoperative angles, all patients except one developed solid fusion. There was no increase in neurologic deficit. One patient developed an asymptomatic pseudarthrosis demonstrated by breakage of both plates through unfilled screw holes at the motion segment. Other complications included one wound infection, one case of arachnoiditis after an intradural bone fragment was excised, and one dural tear created by a Kirschner wire, which did not result in a neurologic deficit or a cerebrospinal fluid leak. The combination of dynamic compression plates and 6.5-mm cancellous screws provided safe and reliable fixation in this series of thoracic and lumbar spine fractures. Whether inability to maintain complete postoperative correction is clinically significant or not is unknown and will require further study.

Closed reduction of cervical spine dislocations.

Between July 1979 and July 1983, 24 patients with cervical facet dislocations were treated. There were 11 unilateral and 13 bilateral facet dislocations. The treatment consisted of axial skeletal tractions, Stryker frame, Gardner-Wells tongs, and judicious manipulation. Cadaver studies were important for learning the anatomy and principles of cervical manipulation. Seventeen (71%) of the 24 patients were reduced successfully by a closed method without any progression of neurologic deficit or facet fracture. Seven (29%) of the 24 patients could not be reduced closed. Ninety percent (9 of 10) of incomplete spinal cord injuries improved when evaluated by the Frankel classification at least one grade. The program of treatment proved to be safe and effective in achieving closed reduction of either unilateral or bilateral facet dislocations.

Spinal fusion : science and technique

I The Science of Spinal Fusions.- 1 History of Spinal Fusion.- 2 The Biology of Spinal Fusion.- 3 Response to Metallic Implants.- 4 Electrical Stimulation of Spinal Fusions.- 5 Biomechanical Principles of Spinal Correction.- II Indications for Spinal Fusion.- 6 Assessing Spinal Instability or Indications for Spinal Fusion.- III Anatomy and Surgical Approaches.- 7 Anatomy and Surgical Approaches of the Spine.- IV Fusion Techniques.- 8 Fusion Techniques for Spinal Infections.- 9 Fusion Techniques for Degenerative Disease.- 10 Fusion Techniques for Tumors.- 11 Fusion Techniques for Traumatic Injuries.- 12 Fusion Techniques for Pediatric Disorders.- 13 Fusion Techniques for Scoliosis.- 14 Fusion Techniques for Adult Spinal Deformity.- V Postoperative Management.- 15 Imaging of Spinal Fusions.- 16 Bracing of Spinal Fusions.- 17 Complications of Spinal Fusions.- VI The Future.- 18 The Future of Spinal Fusions.

Operative neurological complications resulting from thoracic and lumbar spine internal fixation.

Of 2023 patients treated for acute spinal injuries, 729 sustained acute injuries in thoracic and lumbar regions; 295 surgically treated patients were reviewed for evidence of postoperative neurological complications. Of the 295 patients, 150 were intraoperatively monitored using somatosensory-evoked potentials (SSEP). Six patients (4%) revealed intraoperative deterioration of the SSEP; however, only one of the six revealed a new postoperative neurological deficit (0.7%). The remaining 145 patients were included in the unmonitored or wake-up test group in which ten (6.9%) demonstrated new postoperative deficits. Of the 11 patients with new postoperative neurological deficits, eight patients demonstrated motor weakness, two had radiculopathy, and one had bowel-bladder incontinence. The intraoperative use of SSEP was not able to identify subtle alterations in neurological function; however, due to early warning, SSEP appears capable of preventing profound surgically induced neurological alterations. A new protocol is designed for the management of intraoperative neurological deterioration as detected by SSEP.

Magnetic resonance imaging of acute spinal cord trauma: preliminary report

Forty-three magnetic resonance studies were performed on 28 patients with suspected spinal cord injury using a 1.5 Tesla magnet and surface coils. Imaging was performed between day 1 and day 16 post injury. In several patients, repeat magnetic resonance studies were performed to evaluate the resolution of the cord lesions. Three types of magnetic resonance signal patterns were seen in association with the cord injuries. Patients with intraspinal hemorrhage did not have significant neurological recovery, whereas patients with cord edema/contusion recovered significant neurological function. Magnetic resonance imaging appears to be useful in the diagnosis of acute cord injury and also appears to demonstrate the potential for predicting neurological recovery.

The use of autografts for vertebral body replacement of the thoracic and lumbar spine

Thirty-seven patients with fractures of the thoracic or lumbar spine underwent anterior corpectomy (partial or complete) and vertebral body replacement for either destructive lesions from tumor or infection (13 patients) or trauma (24 patients). The vertebral bodies were replaced using either rib (12 patients) or tricortical iliac crest (25 patients) autografts. The Dunn device was utilized in conjunction with the autografts in 19 patients. Posterior stabilization was used in five patients; three prior to anterior stabilization and two after anterior stabilization. Within 2 weeks of the operative procedure, all patients began walking or sitting. Of the 37 patients, 21 with incomplete neurologic deficits improved, and 10 of those went onto complete recovery. Of the 27 patients who have been followed for a minimum of 1 year, 25 have obtained solid fusions, one developed a pseudarthrosis that required regrafting, and one had a delayed union prior to death from metastatic disease. There were two deaths in the immediate postoperative period and three deaths in the first six postoperative wounds due to metastatic disease. The purpose of this study is to present a consecutive series of patients who have undergone corpectomy and vertebral body replacement as well as to define the adequacy of stabilization.

Biomechanical analysis of cervical distraction.

A biomechanical analysis of cervical distraction is presented, and a model comparing closed reduction of cervical spine dislocations to spring mechanics is developed. Behavior of a spring may be described as F = kδx where F = distraction force; δx = elongation of the spring; and k = spring constant. The records and roentgenograms of 24 cervical spine dislocations were reviewed retrospectively. Evaluation of cervical distraction vs traction weight indicates that Ftractlon = kneckδx; where F = traction weight and x = distraction at the injured level. The constant, kneck, is different for bilateral and unilateral dislocations (P <.001) and is a function of magnitude of injury and neck morphology. As determined in this study, traction weight needed for reduction of facet dislocations may be estimated using the formulae: Ftx = 107.1 Ibs/cm (x) unilateral, and Ftx = 76.4 Ibs/cm (x) bilateral.

Intrathoracic chordoma presenting as a posterior superior mediastinal tumor.

A case of thoracic chordoma successfully treated with surgical excision is reported and described. Thoracic chordomata presenting as posterior superior mediastinal tumors occur infrequently and may be highly malignant lesions. Early radical surgery through thoracotomy provide the best hope of cure, and radiation offers only temporary regression of tumor.