Friday, January 4, 2013

Multilevel anterior cervical discectomy and fusion with and without rhBMP-2: a comparison of dysphag

Journal of Neurosurgery: Spine, Volume 18, Issue 1, Page 43-49, January 2013.
Object Reported complications of recombinant human bone morphogenetic protein–2 (rhBMP-2) use in anterior cervical discectomy and fusion (ACDF) cases include dysphagia and cervical swelling. However, dysphagia often occurs after multilevel ACDF procedures performed with allograft (without BMP) as well. To date, there has been no large study comparing the dysphagia rates of patients who have undergone multilevel ACDF using allograft spacers with those who underwent ACDF using polyetheretherketone (PEEK) cages filled with rhBMP2. The authors report one of the first such comparisons between these 2 patient cohorts. Methods The authors retrospectively reviewed 150 patient records. Group 1 (BMP group) consisted of 100 patients who underwent multilevel ACDF with PEEK cages filled with rhBMP-2 and instrumented with a cervical plate. Group 2 (allograft group) included a matched control cohort of 50 patients who underwent multilevel ACDF with allograft spacers and anterior plate fixation (without rhBMP-2). Patient demographics were not significantly different between the groups. Fusion was assessed by means of dynamic radiographs and/or CT at routine intervals. Complications, dysphagia incidence, standardized dysphagia score, Nurick grades, and fusion rates were assessed. Results The mean follow-up for the BMP group (Group 1) was 35 months while the mean follow-up for the allograft group (Group 2) was 25 months. There was a complication rate of 13% in the BMP group compared with 8% in the allograft group (p < 0.005). There was no significant difference in overall dysphagia incidence between the BMP group and the allograft group (40% vs 44%, respectively; p > 0.05). However, there was a significant difference in the severity of dysphagia (using the SWAL-QOL dysphagia scoring system) between the 2 groups: 0.757 for the BMP group versus 0.596 for the allograft group (p < 0.005). In subgroup analysis, the use of rhBMP-2 significantly increased the severity of dysphagia in patients undergoing 2-level ACDF (p < 0.005). However, the severity of dysphagia did not differ significantly between groups when 3- or 4-level ACDF cases were compared. There was no pseudarthrosis in Group 1 (the BMP group) compared with a 16% pseudarthrosis rate in Group 2 (the allograft group) (p < 0.05). There was a weak correlation between the total rhBMP-2 dose and the dysphagia score (Kendall tau rank correlation coefficient 0.166, p = 0.046). Conclusions The use of rhBMP-2 in patients undergoing 2-level ACDF significantly increases the severity of dysphagia (dysphagia score) without affecting the overall incidence of dysphagia. However, there is no statistically significant difference in the incidence or severity of dysphagia between patients undergoing 3-level or 4-level ACDF treated with PEEK/rhBMP-2 and those treated with only allograft. The use of rhBMP-2 appears to reduce the risk of pseudarthrosis. This benefit is most pronounced in patients who undergo 4-level ACDF and are smokers.





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Is inclusion of the occiput necessary in fusion for C1–2 instability in rheumatoid arthritis?

Journal of Neurosurgery: Spine, Volume 18, Issue 1, Page 50-56, January 2013.
Object The atlantoaxial joint is the location most and earliest affected in patients with rheumatoid arthritis (RA). In longstanding disease, ligamentous and osseous destruction can progress and involve all cervical segments. If surgical intervention is necessary, some prefer, to be safe, undertaking fusion to the occiput, whereas others advocate 1-level fusion of C1–2. Sparing the occiput (Oc)–C1 segment would allow retention of a considerable amount of physiological range of motion and seems beneficial against subaxial overload. Previous clinical studies on this topic have provided only nonspecific data after short-term follow-up, rendering a segment-sparing approach questionable. The purpose of the present investigation was to assess long-term progression of inflammatory or degenerative destruction in the Oc–C1 segment after isolated C1–2 fusion for RA. Methods In a series of 113 consecutive patients with RA-related destruction restricted to the craniocervical junction, 14 individuals underwent Oc–C2 fusion and 99 underwent surgery exclusively at the C1–2 level. After a mean follow-up period of 9.4 years (range 4.9–14.7 years), 46 patients were available for clinical and radiographic examination, including CT imaging. Results None of the 46 patients needed additional surgery to extend the fusion to the occiput. Despite marked deterioration in the subaxial cervical spine, in general there were little or no changes in the atlantooccipital region. All but one patient presented with bony fusion of the fixed C1–2 level at follow-up. Conclusions The results of this investigation suggest that if the Oc–C1 joint is free of osseous destructions on conventional radiographs and free of abnormalities on MRI scans at the time of surgery (for transarticular fixation and fusion of C1–2), there is a very low risk for relevant destruction in the following 5–14 years. Thus, no prophylactic oligosegmental approach, but rather a segment-sparing monosegmental approach, is preferred, even in patients with high inflammatory levels.





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In vitro experiment for verification of the tandem shunt valve system: a novel method for treating h

Journal of Neurosurgery: Pediatrics, Volume 11, Issue 1, Page 43-47, January 2013.
Object The CSF shunt valve is a medical device whose main function is to regulate intracranial pressure and drain excess CSF. The authors have developed a new therapeutic method for treating hydrocephalus, namely the tandem shunt valve system, which has the potential of flexibly controlling the CSF flow rate and intracranial pressure in patients. Methods The properties of the tandem system were verified by performing in vitro experiments. An in vitro system with a manometer was built to measure pressure and flow rates of water in open systems using the Codman Hakim Programmable Valve and the Strata adjustable pressure programmable valve. A single valve and 2 single shunt valves connected in series (the tandem shunt valve system) were connected to the manometer to check the final pressure. Results Conventional single shunt valve systems require valve pressures to be set higher to slow down the CSF flow rate, which inevitably results in a higher final pressure. On the other hand, the tandem shunt valve system uses the combination of 2 valves to slow the CSF flow rate without increasing the final pressure. Conclusions The authors succeeded in experimentally demonstrating in vitro results of tandem systems and their effectiveness by applying a model to show that the valve with the higher pressure setting determined the final pressure of the entire system and the flow rate became slower than single shunt valve systems.





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Ventral spinal cerebrospinal fluid leak as the cause of persistent post–dural puncture headache in c

Journal of Neurosurgery: Pediatrics, Volume 11, Issue 1, Page 48-51, January 2013.
Headache occurs after dural puncture in about 1%–25% of children who undergo the procedure—a rate similar to that seen in adults. Persistence of post–dural puncture headache in spite of bed rest, increased fluid intake, and epidural blood patch treatment, however, is rare. The authors reviewed the medical records and imaging studies of all patients 19 years of age or younger who they evaluated between 2001 and 2010 for intracranial hypotension, and they identified 8 children who had persistent post–dural puncture headache despite maximal medical treatment and placement of epidural blood patches. A CSF leak could be demonstrated radiologically and treated surgically in 3 of these patients, and the authors report these 3 cases. The patients were 2 girls (ages 14 and 16 years) who had undergone lumbar puncture for evaluation of headache and fever and 1 boy (age 13 years) who had undergone placement of a lumboperitoneal shunt using a Tuohy needle for treatment of pseudotumor cerebri. The boy also had undergone a laminectomy and exploration of the posterior dural sac, but no CSF leak could be identified. All 3 patients presented with new-onset orthostatic headaches, and in all 3 cases MRI demonstrated a large ventral lumbar or thoracolumbar CSF collection. Conventional myelography or digital subtraction myelography revealed a ventral dural defect at L2–3 requiring surgical repair. Through a posterior transdural approach, the dural defect was repaired using 6-0 Prolene sutures and a dural substitute. Postoperative recovery was uneventful, with complete resolution of orthostatic headache and of the ventral cerebrospinal fluid leak on MRI. The authors conclude that persistent postdural puncture headache requiring surgical repair is rare in children. They note that the CSF leak may be located ventrally and may require conventional or digital subtraction myelography for exact localization and that transdural repair is safe and effective in eliminating the headaches.





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Posthemorrhagic hydrocephalus and shunts: what are the predictors of multiple revision surgeries?

Journal of Neurosurgery: Pediatrics, Volume 11, Issue 1, Page 37-42, January 2013.
Object Cerebrospinal fluid shunts in patients with posthemorrhagic hydrocephalus are prone to failure, with some patients at risk for multiple failures. The objective of this study was to identify factors leading to multiple failures. Methods The authors performed a retrospective analysis of cases of posthemorrhagic hydrocephalus requiring neurosurgical intervention between 1982 and 2010. Results In the 109 cases analyzed, 54% of the patients were male, their mean birth weight was 1223 g, and their mean head circumference 25.75 cm. The mean duration of follow-up was 6 years, and 9 patients died. Grade III intraventricular hemorrhage was seen in 47.7% and Grade IV in 43.1%. Initial use of a ventricular access device was needed in 65 patients (59.6%), but permanent CSF shunting was needed in 104 (95.4%). A total of 454 surgical procedures were performed, including 304 shunt revisions in 78 patients (71.6%). Detailed surgical notes were available for 261 of these procedures, and of these, 51% were proximal revisions, 13% distal revisions, and 17% total shunt revisions. Revision rates were not affected by catheter type, patient sex, presence of congenital anomalies, or type of hydrocephalus. Age of less than 30 days at the initial procedure was associated with decreased survival of the first shunt. Regression analysis revealed that lower estimated gestational age (EGA) and obstructive hydrocephalus were significant predictors of multiple shunt revisions. Conclusions We found a high rate of need for permanent CSF shunts (95.4%) in patients with posthemorrhagic hydrocephalus. Shunt revision was required in 71.6% of patients, with those with lower birth weight and EGA at a higher risk for revisions.





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