Unilateral Minimally Invasive Across-Midline Vertebral Column Resection Partially Corrects Thoracolumbar Kyphosis - A Case Series.

OBJECTIVE: The goal of this study was to describe the indirect and partial correction of spine kyphotic deformities (secondary to various pathologies) achieved by minimally invasive posterolateral extracavitary approach (MIS PLECA) for corpectomy. METHODS: The authors retrospectively reviewed a consecutive case series of 12 patients undergoing MIS PLECA in a single institution. Perioperative data were collected and follow-up computed tomographies and radiographs were reviewed to assess for interbody arthrodesis. RESULTS: The mean age was 60.7 ± 20.8 years (58.4% males). The etiologies of deformity included pathological fracture (41.6%), acute trauma (30%), and infection. An expandable cage was used in 66.7% of patients for anterior reconstruction. The mean total estimated blood loss was 764.1 ± 332.9 ml. The mean operative time was 413.3 ± 98.8 minutes. The average length of hospital stay was 5.8 ± 2.5 days. A consistent degree of focal correction of sagittal alignment was seen in all patients with a mean correction of sagittal angle of 7.4 ± 4.3° (P < 0.0001). The mean duration of rehabilitation was 8.5 ± 6.7 days. All patients remained neurologically stable at the last follow-up with a mean follow-up period of 20.1 ± 12.8 months. Successful fusion was achieved in 91.7% at the last follow-up. CONCLUSIONS: MIS PLECA for corpectomy appears to be a feasible, safe, and effective MIS technique for select patients, particularly those who cannot tolerate the traditional open approach. Additionally, a focal sagittal deformity correction can be achieved using MIS corpectomy.

Candida parapsilosis Infection of Ventriculoperitoneal Shunt in Adult: Case Report and Literature Review.

BACKGROUND: Candida parapsilosis is an incredibly rare cause of ventriculoperitoneal (VP) shunt infections, with only 1 adult case reported in the literature to date. CASE DESCRIPTION: We describe the case of a 45-year-old man admitted for a traumatic fall and subsequently treated with VP shunt placement for obstructive hydrocephalus secondary to a cerebellar contusion and intraventricular hemorrhage. Eight months following VP shunt placement, the patient presented with a 2-month history of clear fluid leakage through a dehiscent surgical abdominal wound overlying the distal VP shunt. Cerebrospinal fluid cultures were obtained and grew C. parapsilosis. The patient subsequently underwent VP shunt externalization and began antifungal treatment with intravenous liposomal amphotericin B. Cerebrospinal fluid studies continued to redemonstrate C. parapsilosis infection, for which VP shunt removal and external ventricular drain placement was performed. Three days into treatment with amphotericin B, he endured significant nephrotoxicity necessitating a switch to oral fluconazole. Following 3 weeks of oral fluconazole treatment with negative serial cerebrospinal fluid cultures, the patient underwent external ventricular drain removal and VP shunt insertion. Following the procedure and 22 total days of oral fluconazole treatment, our patient recovered well and was discharged to a rehabilitation facility in stable condition. CONCLUSIONS: In our report, we describe the clinical course of our patient and offer a review and analysis of the most up-to-date literature concerning C. parapsilosis shunt infections, as well as treatment guidelines for central nervous system candidiasis.

Neurological Outcome Following Surgical Treatment of Spinal Metastases.

BACKGROUND: Spinal metastases lead to bony instability and spinal cord compression resulting in intractable pain and neurological deficits which affect ambulatory function and quality of life. The most appropriate treatment for spinal metastasis is still debated. OBJECTIVE: The aim of this study is to evaluate clinical outcome, quality of life, complications, and survival after surgical treatment of spinal metastases. METHODS: Retrospective review of patients with spinal metastases surgically treated at our facility between March 2008 and March 2013 was performed. Evaluations include hospital charts, initial and interval imaging studies, neurological outcome, and surgical complications. Follow-up examinations were performed every 3 months after surgery. RESULTS: Seventy patients underwent surgical intervention for treatment of spinal metastasis in our institution. There were 27 women and 43 men. The preoperative pain was reported in 65 patients (93%), whereas postoperative complete pain relief was reported in 16 patients (24%), and pain levels decreased in 38 patients (58%). Preoperative 39 patients were ambulant and 31 patients were nonambulant. Postoperative 52 patients were ambulant and 18 patients were nonambulant. Postoperative complications were experienced in 10 (14.2%) patients, and the patient survival rate was 71% (50 patients) at 3 months, 49% (34 patients) at 1 year. The postoperative 30-day mortality rate was 4.2%. CONCLUSION: Surgical decompression for a metastatic spinal tumor can improve the quality of life in a substantially high percentage of patients with acceptable complications rate.

Surgical decompression for recurrent cord compression in cancer: a case series and review of the literature.

Spine metastases affect a significant number of cancer patients each year, with the spine being the third most common location for cancer spread. As patients live longer with improved treatments, the opportunity for recurrence at previously treated sites increases. Here, we describe seven patients with recurrent, compressive, metastatic spine tumors at previously surgically treated sites that required additional surgical intervention with manipulation of at least one rod. Five of the patients had recurrence including adjacent levels while two had recurrence solely at the previously decompressed level. The patients remained ambulatory for an average of 31.2 months after the initial surgery. We also discuss the role of adjuvant treatment in these patients and review the literature.

Predictors of delayed failure of structural kyphoplasty for pathological compression fractures in cancer patients.

OBJECT Pathological compression fractures in cancer patients cause significant pain and disability. Spinal metastases affect quality of life near the end of life and may require multiple procedures, including medical palliative care and open surgical decompression and fixation. An increasingly popular minimally invasive technique to treat metastatic instabilities is kyphoplasty. Even though it may alleviate pain due to pathological fractures, it may fail. However, delayed kyphoplasty failures with retropulsed cement and neural element compression have not been well reported. Such failures necessitate open surgical decompression and stabilization, and cement inserted during the kyphoplasty complicates salvage surgeries in patients with a disease-burdened spine. The authors sought to examine the incidence of delayed failure of structural kyphoplasty in a series of cement augmentations for pathological compression fractures. The goal was to identify risk predictors by analyzing patient and disease characteristics to reduce kyphoplasty failure and to prevent excessive surgical procedures at the end of life. METHODS The authors retrospectively reviewed the records of all patients with metastatic cancer from 2010 to 2013 who had undergone a procedure involving cement augmentation for a pathological compression fracture at their institution. The authors examined the characteristics of the patients, diseases, and radiographic fractures. RESULTS In total, 37 patients underwent cement augmentation in 75 spinal levels during 45 surgeries. Four patients had delayed structural kyphoplasty failure necessitating surgical decompression and fusion. The mean time to kyphoplasty failure was 2.88 ± 1.24 months. The mean loss of vertebral body height was 16% in the patients in whom kyphoplasty failed and 32% in patients in whom kyphoplasty did not fail. No posterior intraoperative cement extravasation was observed in the patients in whom kyphoplasty had failed. The mean spinal instability neoplastic score was 10.8 in the patients in whom kyphoplasty failed and 10.1 in those in whom kyphoplasty did not fail. Approximately 50% of the kyphoplasty failures occurred at junctional spinal levels. All the patients in whom kyphoplasty failed had fractures in 3 or more cortical walls before treatment, whereas 46% of patients in the nonfailure group had fractures with breaching of 3 or more walls. CONCLUSIONS Although rare, delayed failures of structural augmentation with cement during kyphoplasty do occur and can lead to additional surgeries. A possible predictive index may include wall integrity of the vertebral body, competency of the posterior tension band, and location of the kyphoplasty at a junctional spinal level. Additional studies are required to confirm these findings.

Safety of instrumentation in patients with spinal infection.

OBJECT: Treatment of spine infection remains a challenge for spine surgeons, with the most effective method still being a matter of debate. Most surgeons agree that in early stages of infection, antibiotic treatment should be pursued; under certain circumstances, however, surgery is recommended. The goals of surgery include radical debridement of the infective focus. In some cases, when surgery causes mechanical spinal instability, the question arises whether the risk of recurrent infection outweighs the benefits of spinal instrumentation and stabilization. The authors report their series of cases in which instrumentation was placed in actively infected sites and review the relevant literature. METHODS: The authors performed a retrospective analysis of all cases of spinal infection that were surgically treated with debridement and placement of instrumentation at their institution between 2000 and 2006. Patient presentation, risk factor, infective organism, surgical indication, level of involvement, type of procedure, and ultimate outcome were reviewed. Improved outcome was based on improvement of initial American Spinal Injury Association Impairment Score. RESULTS: Forty-seven patients (32 men, 15 women) were treated with instrumented surgery for spinal infection. Their average age at presentation was 54 years (range 37-78 years). Indications for placement of instrumentation included instability, pain after failure of conservative therapy, or both. Patients underwent surgery within an average of 12 days (range 1 day to 5 months) after their presentation to the authors' institution. The average length of hospital stay was 25 days (range 9-78 days). Follow-up averaged 22 months (range 1-80 months). Eight patients died; causes of death included sepsis (4 patients), cardiac arrest (2), and malignancy (2). Only 3 patients were lost to follow-up. Using American Spinal Injury Association scoring as the criterion, the patients' conditions improved in 34 cases and remained the same in 5. Complications included hematoma (2 cases), the need for hardware revision (1), and recurrent infection (2). Hardware replacement was required in 1 of the 2 patients with recurrent infection. CONCLUSIONS: Instrumentation of the spine is safe and has an important role in stabilization of the infected spine. Despite the presence of active infection, we believe that instrumentation after radical debridement will not increase the risk of recurrent infection. In fact, greater benefit can be achieved through spinal stabilization, which can even promote accelerated healing.

Comparison of three methods of targeting the subthalamic nucleus for chronic stimulation in Parkinson's disease.

OBJECTIVE: The success of subthalamic nucleus (STN) surgery for Parkinson's disease depends on accuracy in target determination. The objective of this study was to determine which of the following techniques was most accurate and precise in identifying the location for stimulation in STN deep brain stimulation surgery that is most clinically effective: direct targeting, indirect targeting using the positions of the anterior and posterior commissures, or a technique using the red nucleus (RN) as an internal fiducial marker. METHODS: We reviewed 14 patients with Parkinson's disease treated with bilateral STN deep brain stimulation (28 STN targets). Electrode implantation was based on direct and indirect targeting using two-dimensional magnetic resonance imaging with refinement using microelectrode recording. Optimal settings, including the contacts used, were determined during the clinical follow-up. The position of the best contact was defined with postoperative magnetic resonance imaging. This location was compared with the modified direct, indirect, and RN-based targets. The mean distances between the targets and the final position of the optimal contact were calculated. The accuracy and variance of each target were analyzed. RESULTS: The mean position of the best contact was x = 12.12 (standard deviation [SD], 1.45 mm), y = -2.41 (SD, 1.63 mm), and z = -2.39 (SD, 1.49 mm) relative to the midcommissural point. The mean distance between the optimal contact position and the planned target was 3.19 mm (SD, 1.19 mm) using the RN-based method, 3.42 mm (SD, 1.34 mm) using indirect targeting, and 4.66 mm (SD, 1.33 mm) using a modified direct target. The mean distance between the optimal contact and the RN-based target was significantly smaller than the mean distance between the optimal contact and the direct target (post hoc with Tamhane's correction, P < 0.001) but not between the optimal contact and the indirect target. The RN-based target had the smallest variance (F test, P < 0.001), indicating greater precision. CONCLUSION: The use of the RN as an internal fiducial marker for targeting the optimal region of STN stimulation was reliable and closely approximates the position of the electrode contact that provides the optimal clinical results.

Minimally invasive anterior vertebroplasty for C-2 metastatic lesions.

The authors describe a technique for minimally invasive anterior vertebroplasty for treating metastatic disease of the C-2 vertebra and discuss its application in 2 cases. After a 2-cm lateral neck incision is made, blunt dissection is performed toward the anterior inferior endplate of the C-2 vertebra. An 11-gauge needle is introduced through a tubular sheath and tapped into the inferior endplate of C-2, with biplanar fluoroscopy being performed to confirm position. The needle is subsequently advanced across the fracture line and into the odontoid process. Under fluoroscopic guidance, 2 ml of methylmethacrylate is injected into the odontoid process and vertebral body. This method is advantageous as 1) hyperextension of the neck is not performed, 2) the chance of inadvertent neurovascular or submandibular gland injury is minimized, 3) the possibility of cement leakage is decreased, and 4) hemostasis is better achieved under direct vision.

CASMIL: a comprehensive software/toolkit for image-guided neurosurgeries.

BACKGROUND: CASMIL aims to develop a cost-effective and efficient approach to monitor and predict deformation during surgery, allowing accurate, and real-time intra-operative information to be provided reliably to the surgeon. METHOD: CASMIL is a comprehensive Image-guided Neurosurgery System with extensive novel features. It is an integration of various modules including rigid and non-rigid body co-registration (image-image, image-atlas, and image-patient), automated 3D segmentation, brain shift predictor, knowledge based query tools, intelligent planning, and augmented reality. One of the vital and unique modules is the Intelligent Planning module, which displays the best surgical corridor on the computer screen based on tumor location, captured surgeon knowledge, and predicted brain shift using patient specific Finite Element Model. Also, it has multi-level parallel computing to provide near real-time interaction with iMRI (Intra-operative MRI). In addition, it has been securely web-enabled and optimized for remote web and PDA access. RESULTS: A version of this system is being used and tested using real patient data and is expected to be in use in the operating room at the Detroit Medical Center in the first half of 2006. CONCLUSION: CASMIL is currently under development and is targeted for minimally invasive surgeries. With minimal changes to the design, it can be easily extended and made available for other surgical procedures.

Comparison of three methods of targeting the subthalamic nucleus for chronic stimulation in Parkinson's disease.

OBJECTIVE: The success of subthalamic nucleus (STN) surgery for Parkinson's disease depends on accuracy in target determination. The objective of this study was to determine which of the following techniques was most accurate and precise in identifying the location for stimulation in STN deep brain stimulation surgery that is most clinically effective: direct targeting, indirect targeting using the positions of the anterior and posterior commissures, or a technique using the red nucleus (RN) as an internal fiducial marker. METHODS: We reviewed 14 patients with Parkinson's disease treated with bilateral STN deep brain stimulation (28 STN targets). Electrode implantation was based on direct and indirect targeting using two-dimensional magnetic resonance imaging with refinement using microelectrode recording. Optimal settings, including the contacts used, were determined during the clinical follow-up. The position of the best contact was defined with postoperative magnetic resonance imaging. This location was compared with the modified direct, indirect, and RN-based targets. The mean distances between the targets and the final position of the optimal contact were calculated. The accuracy and variance of each target were analyzed. RESULTS: The mean position of the best contact was x = 12.12 (standard deviation [SD], 1.45 mm), y = -2.41 (SD, 1.63 mm), and z = -2.39 (SD, 1.49 mm) relative to the midcommissural point. The mean distance between the optimal contact position and the planned target was 3.19 mm (SD, 1.19 mm) using the RN-based method, 3.42 mm (SD, 1.34 mm) using indirect targeting, and 4.66 mm (SD, 1.33 mm) using a modified direct target. The mean distance between the optimal contact and the RN-based target was significantly smaller than the mean distance between the optimal contact and the direct target (post hoc with Tamhane's correction, P < 0.001) but not between the optimal contact and the indirect target. The RN-based target had the smallest variance (F test, P < 0.001), indicating greater precision. CONCLUSION: The use of the RN as an internal fiducial marker for targeting the optimal region of STN stimulation was reliable and closely approximates the position of the electrode contact that provides the optimal clinical results.

Bilateral globus pallidus internus deep brain stimulation in tardive dyskinesia: a case report.

The clinical response of a 53-year-old woman with tardive dyskinesia treated with bilateral globus pallidus interna deep brain stimulation is described. At 18 months follow-up, her Burke-Fahn-Marsden Dystonia Rating Scale score fell from 52 (preoperative) to 21 (60% improvement).

Primary dystonia is more responsive than secondary dystonia to pallidal interventions: outcome after pallidotomy or pallidal deep brain stimulation.

OBJECTIVE: The response of patients with dystonia to pallidal procedures is not well understood. In this study, we assessed the postoperative outcome of patients with primary and secondary dystonia undergoing pallidotomy or pallidal deep brain stimulation. METHODS: Fifteen patients with dystonia had pallidal surgery (lesions or deep brain stimulation). These included nine patients with primary dystonia (generalized and cervical dystonias) and six with secondary dystonia (generalized, segmental, and hemidystonias). There were nine male patients and six female patients. The mean age at onset was 21 years for primary dystonia and 18 years for secondary dystonia. The primary outcome measure was a Global Outcome Scale score for dystonia at 6 months after surgery. Other outcome measures were the Burke-Fahn-Marsden Dystonia Rating Scale and Toronto Western Spasmodic Torticollis Rating Scale scores. RESULTS: The mean Global Outcome Scale score at 6 months for patients with primary dystonia was 3 (improvement in both movement disorder and function). In contrast, patients with secondary dystonia had a mean score of 0.83 (mild or no improvement in movement disorder with no functional improvement). All patients with primary dystonia had normal brains by magnetic resonance imaging, whereas five of six patients with secondary dystonia had basal ganglia abnormalities on their magnetic resonance imaging scans. CONCLUSION: This study indicates that primary dystonia responds much better than secondary dystonia to pallidal procedures. We could not distinguish a difference in efficacy between pallidotomy and pallidal deep brain stimulation. The presence of basal ganglia abnormalities on the preoperative magnetic resonance imaging scan is an indicator of a lesser response to pallidal interventions for dystonia.

How does DBS work?

Deep brain stimulation (DBS) produces striking effects in patients with various disorders including Parkinson's disease and dystonia, yet its precise mechanism of action is not clear. Because the clinical benefits of lesioning target structures such as the thalamus, globus pallidus and subthalamic nucleus appear to be similar to those achieved by chronic application of stimulation at these structures, it has been surmized that deep brain stimulation produces a functional inactivation or block of the target. This simplistic proposal has supporting and detracting evidence. In the present work we consider the mechanism of action of DBS and provide arguments for and against the stimulation or inhibition of target neural structures.