Tord D. Alden and Mark D. Krieger
Tord D. Alden, Jeffrey G. Ojemann and T. S. Park
Chiari I malformation is a well-described entity characterized by hindbrain herniation through the foramen magnum. Although the exact origin of congenital Chiari I malformation is unknown, it appears to be caused by a mismatch between the volume of the posterior fossa neural elements and the posterior fossa cranial content. Several theories have been proposed to describe the resultant pathophysiology of this mismatch. It is clear, however, that abnormal cerebrospinal fluid flow and velocity play a role in the symptoms and signs associated with this disorder. The authors will review the pathophysiology, clinical presentation, and treatment options for patients with Chiari I malformation.
Jeffrey C. Rastatter, Patrick C. Walz and Tord D. Alden
The authors of this report present a pediatric case involving the use of a tunneled temporoparietal fascia flap to reconstruct a skull base defect for a multiply recurrent clival chordoma and cerebrospinal fluid leak, demonstrate the surgical technique through illustrations and intraoperative photos, and review the pertinent literature. A 9-year-old female patient underwent extensive clival chordoma resection via both the endoscopic and open approaches, which ultimately exhausted the bilateral nasoseptal flaps and other intranasal reconstructive options. Following proton beam radiation and initiation of chemotherapy, tumor recurrence was managed with further endoscopic resection, which was complicated by a recalcitrant cerebrospinal fluid leak. A tunneled temporoparietal fascia flap was used to provide vascular tissue to augment an endoscopic repair of the leak and reconstruction of the skull base. While the nasoseptal flap remains the workhorse for many pediatric and adult endoscopic skull base reconstructions, the tunneled temporoparietal fascia flap has a demonstrated efficacy in adults when the nasoseptal flap and other intranasal flaps are unavailable. This report documents a pediatric case, serving as a step toward establishing this technique in the pediatric population.
Tord D. Alden, Gerald R. Hankins, Elisa J. Beres, David F. Kallmes and Gregory A. Helm
Gene therapy has many potential applications in neurosurgery. One application involves bone morphogenetic protein-2 (BMP-2), a low-molecular-weight glycoprotein that induces bone formation in vivo. Numerous studies have demonstrated that the BMP-2 protein can enhance spinal fusion. This study was undertaken to determine whether direct injection of an adenoviral construct containing the BMP-2 gene can be used for spinal fusion. Twelve athymic nude rats were used in this study. Recombinant, replication-defective type-5 adenovirus with a universal promoter and BMP-2 gene (Ad-BMP-2) was used. A second adenovirus constructed with a universal promoter and ß-galactosidase (ß-gal) gene (Ad-ß-gal) was used as a control. Seven and one-half microliters of virus was injected percutaneously and paraspinally at the lumbosacral junction in three groups (four animals each): 1) Ad-BMP-2 bilaterally, 2) Ad-BMP-2 on the right, Ad-ß-gal on the left, and 3) Ad-ß-gal bilaterally. Computerized tomography (CT) scans of the lumbosacral spine were obtained at 3, 5, and 12 weeks. At 12 weeks, the animals were killed for histological inspection. Ectopic bone formation was seen both on three-dimensional CT reconstruction and histologically in all rats at sites treated with Ad-BMP-2. Histological analysis revealed bone at different stages of maturity adjacent to the spinous processes, laminae, and transverse processes. This study clearly demonstrated that it is possible to produce in vivo endochondral bone formation by using direct adenoviral construct injection into the paraspinal musculature, which suggests that gene therapy may be useful for spinal fusion in the future.
Tord D. Alden, George J. Kaptain, John A. Jane Jr. and John A. Jane Sr.
The use of chymopapain in the treatment of lumbar disc herniation has been widely studied since Smith first described its use in humans in 1963. The authors describe the use of chymopapain intraoperatively in open lumbar microdiscectomy in 63 patients. When combined with the results of a previous study performed at the same institution, the authors found that this technique significantly reduces the rate of recurrent disc herniation when compared with traditional laminotomy with discectomy. This procedure maximizes the benefits of each approach taken separately, allowing for decompression of the nerve root from a free fragment or sequestered disc and preventing recurrence through dissolution of the nucleus pulposus. Overall, outcome was good or excellent immediately postoperatively in 73% of the 63 patients and in 64% at last follow-up evaluation. Additionally, this procedure is safe with no complications noted in the immediate perioperative period or at follow-up evaluation.
George J. Kaptain, Christopher I. Shaffrey, Tord D. Alden, Jacob N. Young and Richard Whitehill
Although the expectation of monetary compensation has been associated with failures in lumbar discectomy, the issue has not been investigated in patients undergoing cervical disc surgery. The authors analyzed the relationship between economic forms of secondary gain and surgical outcome in a group of patients with a common pay scale, retirement plan, and disability program.
All procedures were performed at the Portsmouth Naval Medical Center between 1993 and 1995; active-duty military servicepersons treated for cervical radiculopathy were prospectively included. Clinical, demographic, and financial factors were analyzed to determine which were predictive of outcome. Financial data were used to create a compensation incentive, which is proportional to the patient's rank, years of service, potential disability, retirement eligibility, and base pay and reflects the monetary incentive of disability. The results of cervical surgery were compared to a previously reported companion population of patients treated for lumbar disc disease. A good outcome was defined as a return to active duty, whereas a referral for disability was considered a poor surgical result. A 100% follow-up rate was obtained for 269 patients who underwent 307 cervical operations. Only 16% (43 of 269) of patients who underwent cervical operation received disability, whereas 24.7% (86 of 348) of patients who underwent lumbar discectomy obtained a poor result (p = 0.0082). Although economic forms of secondary gain were not associated with a poor outcome in cervical disease, both the rank (p = 0.002) and duration (p = 0.03) of an individual's military career were significant factors (p = 0.02). Of the medical variables tested, multilevel surgery (p = 0.03) and revision operations at the same level (p = 0.03) were associated with referral for medical discharge.
Secondary gain in the form of economic compensation influences outcome in lumbar but not cervical disc surgery patients; the increased rate of disability referral in patients who underwent lumbar discectomy may reflect an expectation of economic compensation. Social factors that are independent of the anticipation of economic compensation seem to influence the outcome in cervical disc surgery patients.
John A. Jane Jr., Daniel M. Prevedello, Tord D. Alden and Edward R. Laws Jr.
The majority of pediatric craniopharyngiomas are treated using a transcranial approach. Although there is an increasing acceptance of transsphenoidal resection in adults, there are few reports describing this approach in the pediatric population. The purpose of this study is to report the outcomes after transsphenoidal surgery in a consecutive series of pediatric patients with craniopharyngiomas treated at a single institution with the goal of gross-total resection (GTR).
Twenty-three patients with pathologically proven craniopharyngiomas were identified who were 18 years of age or less at the time of surgery. The medical records and imaging studies of the patients were retrospectively reviewed. One patient who was lost to follow-up after surgery was excluded.
Among the 22 patients included in the study, 11 underwent transsphenoidal surgery as the primary procedure and 11 underwent transsphenoidal surgery as a secondary procedure after a previous procedure. All patients had at least some sellar component to their tumor and all had either anterior or posterior pituitary dysfunction at presentation. In the entire cohort, a GTR was achieved in 15 (68%) of 22 patients, a radical subtotal resection in 4 (18%) of 22 patients, a subtotal resection in 1 patient, and a partial resection in 2 patients. The degree of resection was higher in the primary transsphenoidal group. After a mean follow-up of 82 months, 4 patients (18%) experienced recurrence. Recurrence occurred in 13% after GTR compared with 28.5% after all other degrees of resection. Tumor recurred in 9% of the primary transsphenoidal group and in 30% of patients who had undergone other therapies prior to the transsphenoidal operation. No patient who had panhypopituitarism experienced a gain of function postoperatively, 67% developed new panhypopituitarism, and 56% experienced new diabetes insipidus. Vision improved or normalized in 9 (64%) of 14 patients presenting with visual loss. Complications included 1 death 3 weeks postoperatively, 2 CSF leaks, and new obesity in 37%.
Transsphenoidal resection of pediatric craniopharyngiomas results in a high rate of both visual improvement and GTR with a low associated risk of recurrence. The transsphenoidal approach should be considered in selected pediatric patients with craniopharyngioma, especially those with infradiaphragmatic origin.
Nathan E. Simmons, Tord D. Alden, Michael O. Thorner and Edward R. Laws Jr.
Object. Transsphenoidal surgery remains the optimal treatment for Cushing disease, but the definitions of surgical cure and failure remain debatable. In this study the authors evaluated serum cortisol levels in patients before and after they underwent transsphenoidal surgery to elucidate the patterns of cortisol decrease and the optimal time and criteria for determining surgically induced remission.
Methods. Twenty-seven patients were evaluated throughout an 8-month period. Serum cortisol levels were obtained before surgery and at 6-hour intervals postoperatively. No exogenous steroid medications were administered until after cortisol sampling was discontinued, following diagnosis of remission.
Twenty-one (78%) of 27 cases were labeled initial surgically induced remissions. Twenty-two (81%) of 27 cases were deemed surgically induced remissions at follow-up examination. Following surgery, initial remissions and failures demonstrated divergent patterns of cortisol levels. No patient whose condition was deemed an initial surgically induced remission has experienced definitive relapse of disease since discharge. One patient whose condition was initially deemed a surgical failure, eventually was found to exhibit surgically induced remission without further intervention.
Conclusions. Given such findings, exogenous steroid medications do not appear to be required for patients until after the determination of remission. During the 1st postoperative day, there is a time period during which serum cortisol values significantly differ between the categories of surgically induced remissions and surgical failures. Surgically induced remissions were identified when postoperative values of cortisol were lower than preoperative midnight levels and when absolute values of cortisol were less than 10 µg/dl. In a small proportion of patients remission on a delayed basis may also be demonstrated. These data allow for a simple and rapid determination of postoperative remission in patients undergoing transsphenoidal surgery for Cushing disease.
Anas Al-Smadi, Tahaamin Shokuhfar, Andrew Johnston, Tord D. Alden, Robin Bowman and Ali Shaibani
Intraosseous cranial arteriovenous malformations (AVMs) are very rare, challenging entities. The authors report the case of an extracranial parietooccipital vascular lesion. A 12-year-old boy presented with accelerated growth of a right scalp lesion over a few months. Digital subtraction angiography showed a large, right parietooccipital intraosseous AVM with multiple complex arterial feeders. Treatment of these lesions is difficult and can necessitate a multidisciplinary approach. In the featured case, 6 embolization procedures were performed over 1 year, including both transarterial and transvenous approaches, followed by total resection. The authors describe what is thought to be the second case of an AVM originating in the cranial bones and the first case with successful multidisciplinary management.
Gregory C. Wiggins, Michael J. Rauzzino, Christopher I. Shaffrey, Russ P. Nockels, Richard Whitehill, Mark E. Shaffrey, James Wagner and Tord D. Alden
This study was conducted to determine the safety, efficacy, and complication rate associated with the anterior approach in the use of a new titanium mesh interbody fusion cage for the treatment of unstable thoracolumbar burst fractures. The experience with this technique is compared with the senior authors' (C.S., R.W., and M.S.) previously published results in the management of patients with unstable thoracolumbar burst fractures.
Between 1996 and 1999, 21 patients with unstable thoracolumbar (T12-L3) burst fractures underwent an anterolateral decompressive procedure in which a titanium cage and Kaneda device were used. Eleven of the 21 patients had sustained a neurological deficit, and all patients improved at least one Frankel grade (average 1.2 grades). There was improvement in outcome in terms of blood loss, correction of kyphosis, and pain, as measured on the Denis Pain and Work Scale, in our current group of patients treated via an anterior approach when compared with the results in those who underwent a posterior approach.
In our current study the anterior approach was demonstrated to be a safe and effective technique for the management of unstable thoracolumbar burst fractures. It offers superior results compared with the posterior approach. The addition of the new titanium mesh interbody cage to our previous anterior technique allows the patient's own bone to be harvested from the corpectomy site and used as a substrate for fusion, thereby obviating the need for iliac crest harvest. The use of the cage in association with the Kaneda device allows for improved correction of kyphosis and restoration of normal sagittal alignment in addition to improved functional outcomes.