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Benefit of Transforaminal Lumbar Interbody Fusion vs Posterolateral Spinal Fusion in Lumbar Spine Disorders

tlif-x-ray-lat

Neurosurgery 79:397–405, 2016

Despite increasing use and potential benefits of transforaminal lumbar interbody fusion (TLIF) compared with posterolateral spinal fusion (PSF), previous studies have not documented improved clinical outcomes with TLIF vs PSF.

OBJECTIVE: To compare the outcomes of TLIF with PSF in patients with spondylolisthesis, spinal stenosis, and adjacent level disease.

METHODS: The National Neurosurgical Quality and Outcomes Database was queried for patients who had a lumbar fusion. Eighty-five percent (1722) of enrolled cases had 12-month follow-up data. There were 306 PSF patients and 1230 TLIF patients. PSF cases within each diagnostic subgroup were propensity-matched to patients who had TLIF. Sufficient propensity-matched controls were available for patients with spondylolisthesis (109), spinal stenosis (63), and adjacent segment disease (47).

RESULTS: Operating room time, estimated blood loss, and length of stay were similar between PSF and TLIF in all 3 propensity-matched groups. In the spondylolisthesis group, there was a greater improvement in Oswestry Disability Index (ODI) with TLIF vs PSF at 3 months (19.4 vs 26.0, P = .009), 12 months (20.8 vs 29.3, P = .001), and in percentage reaching minimal clinically important difference at 12 months (80% vs 62%, P = .007). There were no differences in ODI improvement between PSF and TLIF in the stenosis or adjacent segment disease groups.

CONCLUSION: TLIF generated more favorable ODI outcomes than PSF for patients with spondylolisthesis, but not for patients with spinal stenosis or adjacent segment disease. There was also equivalence in operating room time and estimated blood loss between TLIF and PSF, potentially altering the long-standing assumption that PSF is a simpler procedure.

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Stereotactic biopsy of brainstem lesions: 21 years experiences of a single center

Stereotactic biopsy of brainstem lesions- 21 years experiences of a single center

J Neurooncol (2016) 129:243–250

Stereotactic biopsies are procedures performed to obtain tumor tissue for diagnostic examinations. Cerebral lesions of unknown entities can safely be accessed and tissue can be examined, resulting in correct diagnosis and according treatment. Stereotactic procedures of lesions in highly eloquent regions such as the brainstem have been performed for more than two decades in our department.

In this retrospective study we focus on results, approaches, modalities of anesthesia, and complications. We performed a retrospective analysis of our prospective database, including 26 patients who underwent stereotactic biopsy of the brainstem between April 1994 and June 2015.

All of the patients underwent preoperative MRI. Riechert– Mundinger-frame was used before 2000, thereafter the Leksell stereotactic frame was used. After 2000 entry and target points were calculated by using BrainLab stereotactic system. We evaluated histopathological results as well as further treatment; additionally we compared complications of local versus general anesthesia and complications of a frontal versus a trans-cerebellar approach. Median age of all patients was 33 years, and median number of tissue samples taken was 12. In all patients a final histopathological diagnosis could be established. 5 patients underwent the procedure under local anesthesia, 21 patients in general anesthesia. In 19 patients a frontal approach was performed, while in 7 patients a trans-cerebellar approach was used. Complications occurred in five patients. Thereby no significant difference was found with regard to approach (frontal versus trans-cerebellar) or anesthesia (local versus general).

Stereotactic biopsies even of lesions in the brainstem are a save way to obtain tumor tissue for final diagnosis, resulting in adequate treatment. Approach can be trans-cerebellar or frontal and procedure can be performed either under local or general anesthesia without significant differences concerning complication rate.

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STN DBS for Parkinson’s disease: results from a series of ten consecutive patients implanted under general anaesthesia with intraoperative use of 3D fluoroscopy to control lead placement

Artis Zeego

Acta Neurochir (2016) 158:1783–1788

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a recognised treatment for advanced Parkinson’s disease (PD). We present our results of 10 consecutive patients implanted under general anaesthesia (GA) using intraoperative robotic three-dimensional (3D) fluoroscopy (Artis Zeego; Siemens, Erlangen, Germany).

Method Ten patients (nine men, one woman) with a mean age of 57.6 (range, 41–67) years underwent surgery between October 2013 and January 2015. The mean duration of PD was 9.2 [1–10] year. The procedure was performed under GA: placement of the stereotactic frame, implantation of the electrodes (Lead 3389; Medtronic, Minnesota,MN, USA) and 3D intraoperative fluoroscopic control (Artis Zeego) with image fusion with the preoperative MRI scans. All patients were evaluated preoperatively and 6 months postoperatively.

Results The mean operative time was 240.1 (185–325) min. Themean Unified Parkinson’s Disease Rating Scale (UPDRS) II OFF medication decreased from 23.9 preoperatively to 15.7 postoperatively. The mean OFF medication UPDRS III decreased from 41 to 11.6 and the UPDRS IV decreased from 10.6 to 7. The mean preoperative and postoperative L-Dopa doses were 1,178.5 and 696.5 mg, respectively. Two complications were recorded: one episode of transient confusion (24 h) and one internal pulse generator (IPG) infection.

Conclusions With improvement in preoperative magnetic resonance imaging (MRI) and the ability to control the position of the leads intraoperatively using Artis Zeego, we now perform this procedure under GA. Our results are comparable to others reported. The significant decrease in the duration of surgery could be associated with a reduced rate of complications (infection, loss of patient collaboration). However, this observation needs to be confirmed.

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Hydrocephalus: cerebral aquaporin-4 and computational modeling

Aquaporin-4 channels

Neurosurg Focus 41 (3):E8, 2016

Aquaporin-4 (AQP4) channels play an important role in brain water homeostasis. Water transport across plasma membranes has a critical role in brain water exchange of the normal and the diseased brain. AQP4 channels are implicated in the pathophysiology of hydrocephalus, a disease of water imbalance that leads to CSF accumulation in the ventricular system. Many molecular aspects of fluid exchange during hydrocephalus have yet to be firmly elucidated, but review of the literature suggests that modulation of AQP4 channel activity is a potentially attractive future pharmaceutical therapy. Drug therapy targeting AQP channels may enable control over water exchange to remove excess CSF through a molecular intervention instead of by mechanical shunting.

This article is a review of a vast body of literature on the current understanding of AQP4 channels in relation to hydrocephalus, details regarding molecular aspects of AQP4 channels, possible drug development strategies, and limitations. Advances in medical imaging and computational modeling of CSF dynamics in the setting of hydrocephalus are summarized.

Algorithmic developments in computational modeling continue to deepen the understanding of the hydrocephalus disease process and display promising potential benefit as a tool for physicians to evaluate patients with hydrocephalus.

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Human Connectome-Based Tractographic Atlas of the Brainstem Connections and Surgical Approaches

Human Connectome-Based Tractographic Atlas of the Brainstem Connections and Surgical Approaches

Neurosurgery 79:437–455, 2016

The brainstem is one of the most challenging areas for the neurosurgeon because of the limited space between gray matter nuclei and white matter pathways. Diffusion tensor imaging–based tractography has been used to study the brainstem structure, but the angular and spatial resolution could be improved further with advanced diffusion magnetic resonance imaging (MRI).

OBJECTIVE: To construct a high–angular/spatial resolution, wide-population–based, comprehensive tractography atlas that presents an anatomical review of the surgical approaches to the brainstem.

METHODS: We applied advanced diffusion MRI fiber tractography to a population-based atlas constructed with data from a total of 488 subjects from the Human Connectome Project-488. Five formalin-fixed brains were studied for surgical landmarks. Luxol Fast Blue–stained histological sections were used to validate the results of tractography.

RESULTS: We acquired the tractography of the major brainstem pathways and validated them with histological analysis. The pathways included the cerebellar peduncles, corticospinal tract, corticopontine tracts, medial lemniscus, lateral lemniscus, spinothalamic tract, rubrospinal tract, central tegmental tract, medial longitudinal fasciculus, and dorsal longitudinal fasciculus. Then, the reconstructed 3-dimensional brainstem structure was sectioned at the level of classic surgical approaches, namely supracollicular, infracollicular, lateral mesencephalic, perioculomotor, peritrigeminal, anterolateral (to the medulla), and retro-olivary approaches.

CONCLUSION: The advanced diffusion MRI fiber tracking is a powerful tool to explore the brainstem neuroanatomy and to achieve a better understanding of surgical approaches.

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Neuroendoscopic intracranial stenting in adults

Neuroendoscopic

J Neurosurg 125:576–584, 2016

Since its revival in the early 1990s, neuroendoscopy has become an integral component of modern neurosurgery. Endoscopic stent placement for treatment of CSF pathway obstruction is a rarely used and underestimated procedure. The authors present the first series of neuroendoscopic intracranial stenting for CSF pathway obstruction in adults with associated results and complications spanning a long-term follow-up of 20 years.

Methods The authors retrospectively reviewed a prospectively maintained clinical database for endoscopic stent placement performed in adults between 1993 and 2013.

Results Of 526 endoscopic intraventricular procedures, stents were placed for treatment of CSF disorders in 25 cases (4.8%). The technique was used in the management of arachnoid cysts (ACs; n = 8), tumor-related CSF disorders (n = 13), and hydrocephalus due to stenosis of the foramen of Monro (n = 2) or aqueduct (n = 2). The mean follow-up was 87.1 months. No deaths or infections occurred that were related to endoscopic placement of intracranial stents. Late stent dislocation or migration was observed in 3 patients (12%).

Conclusions Endoscopic intracranial stent placement in adults is rarely required but is a safe and helpful technique in select cases. It is indicated when reliable and long-lasting restoration of CSF pathway obstructions cannot be achieved with standard endoscopic techniques. In the treatment of tumor-related hydrocephalus, it is a good option to avoid reclosure of the restored CSF pathway by tumor growth. Currently, routine stent placement after endoscopic fenestration of ACs is not recommended. Stent placement for treatment of CSF disorders due to tumor is a good option for avoiding CSF shunting. To avoid stent migration and dislocation, and to allow for easy removal if needed, the device should be fixed to a bur hole reservoir.

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A study of prognostic factors in 45 cases of atypical meningioma

Radiation Therapy for Residual or Recurrent Atypical Meningioma

Acta Neurochir (2016) 158:1661–1667

Atypical meningioma differs from Grade I meningioma in terms of high recurrence rate and short life expectancy. We evaluated the clinical course of atypical meningioma and investigated prognostic factors affecting its outcomes.

Method: We reviewed 45 patients with atypical meningioma who underwent surgical intervention between January 2000 and December 2013. The mean age of the patients and mean follow-up period was 58.7 years and 81.0 months, respectively. Analyses included factors such as patient age, gender, location and size of tumor, extent of surgical resection (Simpson Grading System), and MIB-1 labeling index (LI). Univariate analysis was used to detect prognostic factors associated with recurrence and survival.

Results: The 5-year recurrence-free rate for all 45 patients was 58.4 %; 5 and 10-year survival rates were 83.2 % and 79.9 %, respectively. In univariate analyses, age >60 years, and MIB-1 LI correlated with disease recurrence, whereas age >60 years, subtotal surgical resection, MIB-1 LI, and indication for radiotherapy correlated with death. MIB-1 LI levels higher than 12.8 % and 19.7 % predicted recurrence and death, respectively. In our cohort, 26 patients received postoperative radiotherapy including conventional radiation (n = 21) or gamma knife radiosurgery (n = 5). Postoperative radiotherapy did not decrease recurrence rates in our cohort (p = 0.63). Six and two patients who died during the study period underwent conventional radiation and radiosurgery, respectively.

Conclusions: Age, male gender, extent of surgical resection, and higher MIB-1 LI influenced the outcome of atypical meningioma. In our cohort, postoperative radiotherapy failed to provide long-term tumor control. Following incomplete surgical resection of atypical meningioma in elderly patients, adjuvant postoperative radiotherapy may not be an ideal treatment option, particularly when MIB-1 LI is higher than 19.7 %.

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Hemodynamic and morphological characteristics of unruptured posterior communicating artery aneurysms with oculomotor nerve palsy

Hemodynamic and morphological characteristics of unruptured posterior communicating artery aneurysms with oculomotor nerve palsy

J Neurosurg 125:264–268, 2016

Unruptured posterior communicating artery (PCoA) aneurysms with oculomotor nerve palsy (ONP) have a very high risk of rupture. This study investigated the hemodynamic and morphological characteristics of intracranial aneurysms with high rupture risk by analyzing PCoA aneurysms with ONP.

Methods: Fourteen unruptured PCoA aneurysms with ONP, 33 ruptured PCoA aneurysms, and 21 asymptomatic unruptured PCoA aneurysms were included in this study. The clinical, morphological, and hemodynamic characteristics were compared among the different groups.

Results: The clinical characteristics did not differ among the 3 groups (p > 0.05), whereas the morphological and hemodynamic analyses showed that size, aspect ratio, size ratio, undulation index, nonsphericity index, ellipticity index, normalized wall shear stress (WSS), and percentage of low WSS area differed significantly (p < 0.05) among the 3 groups. Furthermore, multiple comparisons revealed that these parameters differed significantly between the ONP group and the asymptomatic unruptured group and between the ruptured group and the asymptomatic unruptured group, except for size, which differed significantly only between the ONP group and the asymptomatic unruptured group (p = 0.0005). No morphological or hemodynamic parameters differed between the ONP group and the ruptured group.

Conclusions: Unruptured PCoA aneurysms with ONP demonstrated a distinctive morphological-hemodynamic pattern that was significantly different compared with asymptomatic unruptured PCoA aneurysms and was similar to ruptured PCoA aneurysms. The larger size, more irregular shape, and lower WSS might be related to the high rupture risk of PCoA aneurysms.

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Dynamic posterior stabilization for degenerative lumbar spine disease

DSS

Eur Spine J (2016) 25:2563–2570

Dynamic stabilization of the degenerated spine was invented to overcome the negative side effects of fusion surgery like adjacent segment degeneration. Amongst various different implants DSS  is a pedicle-based dynamic device for stabilizing the spine and preserving motion. Nearly no clinical data of the implant have been reported so far. The current analysis presents results from a single spine surgeon who has been using DSS  for the past 5 years and recorded all treatment and outcome data in the international Spine Tango registry.

Materials/methods: From the prospectively documented overall patient pool 436 cases treated with DSS  could be identified. The analysis was enhanced with a mailing of COMI patient questionnaires for generating longer-term follow-ups up to 4 years.

Results: 387 patients (189 male, 198 female; mean age 67.3 years) with degenerative lumbar spinal disease including degenerative spondylolisthesis (6.1 %) could be evaluated. The type of degeneration was mainly spinal stenosis (89.9 %). After a mean follow-up of 1.94 years, the COMI score and NRS back and leg pain improved significantly and to a clinically relevant extent. The postoperative trend analysis could not determine a relevant deterioration of these outcomes until 4 years postoperative. 10 patients were revised (2.6 %) and the implant was removed; in most cases, a fusion was performed. Another 5 cases (1.3 %) had an extension of the dynamic stabilization system to the adjacent level. 84.2 % of patients rated that the surgery had helped a lot or had helped.

Discussion: The results of this large consecutive series with a follow-up up to 4 years could demonstrate a good and stable clinical outcome after posterior dynamic stabilization with DSS. For degenerative diseases of the lumbar spine, this treatment seems to be a valid alternative to fusion surgery.

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Opening the Internal Hematoma Membrane Does Not Alter the Recurrence Rate of Chronic Subdural Hematomas: A Prospective Randomized Trial

Is systematic post-operative CT scan indicated after chronic subdural hematoma surgery?

WORLD NEUROSURGERY 92: 31-36, AUGUST 2016

Factors determining the recurrence of chronic subdural hematomas (CSDHs) are not clear. Whether opening the so-called internal hematoma membrane is useful has not been investigated.

OBJECTIVE: To investigate whether splitting the inner hematoma membrane influences the recurrence rate in patients undergoing burr-hole craniotomy for CSDH.

METHODS: Fifty-two awake patients undergoing surgery for 57 CSDHs were prospectively randomized to either partial opening of the inner hematoma membrane (group A) or not (group B) after enlarged burr-hole craniotomy and hematoma evacuation. Drainage was left in situ for several days postoperatively. Groups were comparable with regard to demographic, clinical, and imaging variables. Outcome was assessed after 3e6 weeks for the combined outcome variable of reoperation or residual hematoma of one third or more of the original hematoma thickness.

RESULTS: Fourteen patients underwent reoperation for clinical deterioration or residual hematoma during follow- up (n = 6 in group A, 21%; n = 8 in group B, 28 %) (P = 0.537). Residual hematoma of ≥ one third not requiring surgery was present in 7 patients in group A (25%) and 10 patients in group B (36%) (P = 0.383). The overall cumulative failure rate (reoperation or hematoma thickness ≥ one third) was 13/28 (46%) in group A and 18/28 in group B (P = 0.178; relative risk, 0.722 [95% confidence interval, 0.445-1.172]; absolute risk reduction -16% =95% confidence interval, -38% to 8%]).

CONCLUSIONS: Opening the internal hematoma membrane does not alter the rate of patients requiring revision surgery and the number of patients showing a marked residual hematoma 6 weeks after evacuation of a CSDH.

 

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Interventional magnetic resonance imaging‑guided subthalamic nucleus deep brain stimulation for Parkinson’s disease: Patient selection

iMRI STN DBS

Surg Neurol Int 02-Aug-2016;7:

Interventional magnetic resonance imaging (iMRI) guided deep brain stimulation (DBS) for Parkinson’s disease (PD) has been shown to be effective. The costs of a dedicated intraoperative MRI may be prohibitive. The procedure can also be performed in a diagnostic scanner, however this presents challenges for utilization of time when the scanner is used both as a diagnostic and an interventional unit. This report outlines our novel methodology for patient selection for implantation in a diagnostic MR scanner, as an attempt to streamline the use of resources. A retrospective review of our outcomes is also presented.

Methods: DBS candidacy evaluation included a PD questionnaire‑39. Anxiety, age, difficulties in communication and body habitus were factors that were assessed in selecting patients for this technique. Eleven patients underwent iMRI‑guided DBS implantation in the subthalamic nucleus. All patients were implanted bilaterally. Unified PD rating scale (UPDRS) part III and L‑dopa dose were compared pre‑ and post‑stimulation. A cohort of 11 DBS patients not selected for iMRI‑guided DBS were also reported for comparison.

Results: For the iMRI‑guided patients, mean “Off” UPDRS III score was 47.6 (standard deviation [SD] 8.26). Postoperative “On” medication, “On” stimulation UPDRS III was 13.6 (SD 5.23). Mean preoperative L‑dopa dose was 1060 mg (SD 474.3) and mean postoperative L‑dopa dose was 320 (SD 298.3).

Conclusion: iMRI‑guided DBS is a newly emerging technique for surgical treatment of patients with PD. We present a novel scoring system for patient selection assessing anxiety, age, ability to communicate, and body habitus to identify patients who will be benefited most from this technique.

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Internal and external spheno-orbital meningioma varieties: different outcomes and prognoses

SO Meningiomas

Acta Neurochir (2016) 158:1587–1596

Internal variation among spheno-orbital meningiomas  (SOM) is surgically challenging. Optic canal invasion  management is discussed.

Method This retrospective study includes 70 patients with  SOM who underwent surgery between 1995 and 2012.  Preoperative ophthalmological, neurological and aesthetic  clinical signs were collected. All patients benefitted from repeated  tomography and magnetic resonance imaging (MRI).  The surgical team consisted of a neurosurgeon and a plastic  surgeon. In the majority of cases, resection was followed by  bone reconstruction using an autologous iliac crest graft. The  extent of resection was evaluated on the dural and osseous  sides. Early clinical outcomes, long-term follow-up, recurrence  and adjuvant therapies were reported.

Results The mean age was 52 years old, and 91 % of the  patients were women. Initial symptoms primarily included  proptosis (65 %), decreased visual acuity (39 %) and soft  tissue tumefaction (16 %).We classified 40 cases as the internal  variety when considering the inner third of the greater  wing of the sphenoid, optic canal, anterior clinoid process or  cavernous sinus. The remaining cases were described as the  external variety. The complete resection rates for the internal  and external varieties were 12 % and 61 %, respectively  (P< 0.001). In total, 90% of cases were grade I meningiomas.  For grade I, we reported 30 % recurrence, and 50 % of these  cases recurred in the first 2 years. Grade II cases without early  adjuvant radiotherapy increased at 2 years.We did not observe  any difference in recurrence rate among grade I tumours with  or without tumour remnants. At the end of follow-up, visual  acuity was stabilised or increased in 88 % of patients. In addition,  14 % of patients experienced persistent pain at the  location of the iliac harvesting site.

Conclusions The internal SOM variety exhibited a reduced  total resection rate and a shorter progression-free survival  (PFS). Unroofing of the optic canal extended PFS. Among  grade I cases, the persistence of a negligible tumour remnant  did not alter the probability of recurrence. For superior grades,  radiotherapy must be administered in addition to surgery as  soon as possible. SOMs require prolonged follow-up.  Autologous iliac reconstruction is related to substantial morbidity  and could be replaced by prosthetic bone threedimensional  reconstruction.

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Surgery for adult spondylolisthesis: a systematic review of the evidence

spondylolistesis

Eur Spine J (2016) 25:2359–2367

Surgery for isthmic and degenerative spondylolisthesis (SL) in adults is carried out very frequently in everyday practice. However, it is still unclear whether the results of surgery are better than those of conservative treatment and whether decompression alone or instrumented fusion with decompression should be recommended. In addition, the role of reduction is unclear.

Four clinically relevant key questions were addressed in this study: (1) Is surgery more successful than conservative treatment in relation to pain and function in adult patients with isthmic SL? (2) Is surgery more successful than conservative treatment in relation to pain and function in adult patients with degenerative SL? (3) Is instrumented fusion with decompression more successful in relation to pain and function than decompression alone in adult patients with degenerative SL and spinal canal stenosis? (4) Is instrumented fusion with reduction more successful in relation to pain and function than instrumented fusion without reduction in adult patients with isthmic or degenerative SL?

A systematic PubMed search was carried out to identify randomized and nonrandomized controlled trials on these topics. Papers were analyzed systematically in a search for the best evidence.A total of 18 studies was identified and analyzed: two for question 1, eight for question 2, four for question 3, and four for question 4.

Surgery appears to be better than conservative treatment in adults with isthmic SL (poor evidence) and also in adults with degenerative SL (good evidence). Instrumented fusion with decompression appears to be more successful than decompression alone in adults with degenerative SL and spinal stenosis (poor evidence). Reduction and instrumented fusion does not appear to be more successful than instrumented fusion without reduction in adults with isthmic or degenerative SL (moderate evidence).

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Comparing Preoperative With Postoperative Stereotactic Radiosurgery for Resectable Brain Metastases

Motor function after stereotactic radiosurgery for brain metastases in the region of the motor cortex

Neurosurgery 79:279–285, 2016

Stereotactic radiosurgery (SRS) is an increasingly common modality used with surgery for resectable brain metastases (BM).

OBJECTIVE: To present a multi-institutional retrospective comparison of outcomes and toxicities of preoperative SRS (Pre-SRS) and postoperative SRS (Post-SRS).

METHODS: We reviewed the records of patients who underwent resection of BM and either Pre-SRS or Post-SRS alone between 2005 and 2013 at 2 institutions. Pre-SRS used a dose-reduction strategy based on tumor size, with planned resection within 48 hours. Cumulative incidence with competing risks was used to determine estimated rates.

RESULTS: A total of 180 patients underwent surgical resection for 189 BM: 66 (36.7%) underwent Pre-SRS and 114 (63.3%) underwent Post-SRS. Baseline patient characteristics were balanced except for higher rates of performance status 0 (62.1% vs 28.9%, P < .001) and primary breast cancer (27.2% vs 10.5%, P = .010) for Pre-SRS. Pre-SRS had lower median planning target volume margin (0 mm vs 2 mm) and peripheral dose (14.5 Gy vs 18 Gy), but similar gross tumor volume (8.3 mL vs 9.2 mL, P = .85). The median imaging follow-up period was 24.6 months for alive patients. Multivariable analyses revealed no difference between groups for overall survival (P = .1), local recurrence (P = .24), and distant brain recurrence (P = .75). Post-SRS was associated with significantly higher rates of leptomeningeal disease (2 years: 16.6% vs 3.2%, P = .010) and symptomatic radiation necrosis (2 years: 16.4% vs 4.9%, P = .010).

CONCLUSION: Pre-SRS and Post-SRS for resected BM provide similarly favorable rates of local recurrence, distant brain recurrence, and overall survival, but with significantly lower rates of symptomatic radiation necrosis and leptomeningeal disease in the Pre-SRS cohort. A prospective clinical trial comparing these treatment approaches is warranted.

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Biodegradable anterior cervical plates

biodegradable anterior cervical plate

J Neurosurg Spine 25:205–212, 2016

The purpose of this study was to present an initial surgical experience in the management of 1- or 2-level degenerative disc disease of the cervical spine using biodegradable anterior cervical plates (bACPs) in anterior cervical discectomy and fusion (ACDF). The authors also aimed to provide insight into this critical and controversial clinical issue by clarifying outcomes for patients receiving bACPs and by comparing their outcomes with those achieved using a traditional metallic anterior cervical plate (mACP) implant.

Methods: A retrospective review was conducted for 2 series of patients who had undergone ACDF using either bACP (31 patients, 38 segments) or mACP (47 patients, 57 segments) instrumentation. The patients were followed up for a mean 13.5 ± 0.9 months (range 12–18 months) in the bACP group and 14.8 ± 1.5 months (range 14–22 months) in the mACP group. Clinical outcomes were determined according to scores on the visual analog scale (VAS), the modified Japanese Orthopaedic Association (mJOA) scoring system, and Odom’s criteria. Radiological images were used to assess fusion rates, intervertebral height, Cobb’s angle, and the width of prevertebral soft tissue.

Results: Both VAS and mJOA scores were significantly improved at each follow-up in both groups. Excellent or good results according to Odom’s criteria were achieved in 93.5% (29/31) of patients in the bACP group and 93.6% (44/47) of patients in the mACP group. At 6 months postoperatively, the fusion rate was 94.7% (36/38) in the bACP group and 96.5% (55/57) in the mACP group, but subsidence of the intervertebral space at the surgical level was more evident in the bACP group. Angulation, as measured by Cobb’s angle, demonstrated obvious healing in both groups, while better maintenance was observed in the mACP group. The local inflammatory reaction was uneventful during follow-up. Dysphonia and dysphagia were observed in both groups during the follow-up.

Conclusions: The relatively comparable early clinical and radiographic outcomes and the overall acceptable complication rates for bACP and mACP use suggest that bACPs could be used as alternative instruments in ACDF. Mild graft resorption was noted without evidence of symptoms. However, the prospective efficacy of biodegradable instrumentation can only be elucidated with longer-term observation.

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Pituitary Dysfunction After Aneurysmal Subarachnoid Hemorrhage

A Simple and Quantitative Method to Predict Symptomatic Vasospasm After Subarachnoid Hemorrhage Based on Computed Tomography- Beyond the Fisher Scale

Neurosurgery 79:253–264, 2016

The prevalence of hypothalamic-pituitary dysfunction after aneurysmal subarachnoid hemorrhage has not been precisely determined, and conflicting results have been reported in the literature.

OBJECTIVE: To perform a systematic review and meta-analysis investigating the prevalence of pituitary insufficiency after aneurysmal subarachnoid hemorrhage and to focus on basal serum and dynamic test differences.

METHODS: The prevalence of pituitary dysfunction was quantified at 3 to 6 months and .6 months after aneurysmal subarachnoid hemorrhage. Proportions were transformed with the logit transformation. A subgroup analysis was performed focusing on the differences in outcome between basal serum and dynamic tests for the diagnosis of growth hormone deficiency (GHD) and secondary adrenal insufficiency.

RESULTS: Overall prevalence of hypopituitarism differed considerably between studies, ranging from 0.05 to 0.45 in studies performed between 3 and 6 months after the event and from 0 to 0.55 in long-term studies (.6 months), with pooled frequencies of 0.31 (95% confidence interval [CI]: 0.22-0.43) and 0.25 (95% CI: 0.16-0.36), respectively. Pooled frequency of GHD at 3 to 6 months was 0.14 (95% CI: 0.08-0.24). At .6 months, GHD prevalence was 0.19 (95% CI: 0.13-0.26) overall, but ranged from 0.15 (95% CI: 0.06-0.33) with the insulin tolerance test to 0.25 (95% CI: 0.15-0.36) using the growth hormone releasing hormone 1 arginine test.

CONCLUSION: Hypopituitarism is a common complication in patients with aneurysmal subarachnoid hemorrhage, with GHD being the most prevalent diagnosis. We showed that variations in prevalence rates in the literature are partly due to methodological differences among pituitary function tests.

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Binostril versus mononostril approaches in endoscopic transsphenoidal pituitary surgery

Binostril versus mononostril approaches in endoscopic transsphenoidal pituitary surgery

J Neurosurg 125:334–345, 2016

Over the past 2 decades, endoscopy has become an integral part of the surgical repertoire for skull base procedures. The present clinical evaluation and cadaver study compare binostril and mononostril endoscopic transnasal approaches and the surgical techniques involved.

Methods: Forty patients with pituitary adenomas were treated with either binostril or mononostril endoscopic surgery. Neurosurgical, endocrinological, ophthalmological, and neuroradiological examinations were performed. Ten cadaver specimens were prepared, and surgical aspects of the preparation and neuroradiological examination were documented.

Results: In the clinical evaluation, 0° optics were optimal in the nasal and sphenoidal phase of surgery for both techniques. For detection of tumor remnants, 30° optics were superior. The binostril approach was significantly more time consuming than the mononostril technique. The nasal retractor limited maneuverability of instruments during mononostril approaches in 5 of 20 patients. Endocrinological pituitary function, control of excessive hormone secretion, ophthalmological outcome, residual tumor, and rates of adverse events, such as CSF leaks and diabetes insipidus, were similar in both groups. In the cadaver study, there was no significant difference in the time required for dissection via the binostril or mononostril technique. The panoramic view was superior in the binostril group; this was due to the possibility of wider opening of the sella in the craniocaudal and horizontal directions, but the need for removal of more of the nasal septum was disadvantageous.

Conclusions: Because of maneuverability of instruments and a wider view in the sphenoid sinus, the binostril technique is superior for resection of large tumors with parasellar and suprasellar expansion and tumors requiring extended approaches. The mononostril technique is preferable for tumors with limited extension in the intra- and suprasellar area.

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Resection of spinal column tumors utilizing image-guided navigation: a multicenter analysis

IG spinal tumor resection.1

Neurosurg Focus 41 (2):E15, 2016

The use of intraoperative stereotactic navigation has become more available in spine surgery. The authors undertook this study to assess the utility of intraoperative CT navigation in the localization of spinal lesions and as an intraoperative tool to guide resection in patients with spinal lesions.

Methods This was a retrospective multicenter study including 50 patients from 2 different institutions who underwent biopsy and/or resection of spinal column tumors using image-guided navigation. Of the 50 cases reviewed, 4 illustrative cases are presented. In addition, the authors provide a description of surgical technique with image guidance.

Results The patient group included 27 male patients and 23 female patients. Their average age was 61 ± 17 years (range 14–87 years). The average operative time (incision to closure) was 311 ± 188 minutes (range 62–865 minutes). The average intraoperative blood loss was 882 ± 1194 ml (range 5–7000 ml). The average length of hospitalization was 10 ± 8.9 days (range 1–36 days). The postoperative complications included 2 deaths (4.0%) and 4 radiculopathies (8%) secondary to tumor burden.

Conclusions: O-arm 3D imaging with stereotactic navigation may be used to localize lesions intraoperatively with real-time dynamic feedback of tumor resection. Stereotactic guidance may augment resection or biopsy of primary and metastatic spinal tumors. It offers reduced radiation exposure to operating room personnel and the ability to use minimally invasive approaches that limit tissue injury. In addition, acquisition of intraoperative CT scans with real-time tracking allows for precise targeting of spinal lesions with minimal dissection.

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Validity and Reliability of a Measurement of Objective Functional Impairment in Lumbar Degenerative Disc Disease: The Timed Up and Go (TUG) Test

Validity and Reliability of a Measurement of Objective Functional Impairment in Lumbar Degenerative Disc Disease- The Timed Up and Go (TUG) Test

Neurosurgery 79:270–278, 2016

There are few objective measures of functional impairment to support clinical decision making in lumbar degenerative disc disease (DDD).

OBJECTIVE: We present the validation (and reliability measures) of the Timed Up and Go (TUG) test.

METHODS: In a prospective, 2-center study, 253 consecutive patients were assessed using the TUG test. A representative cohort of 110 volunteers served as control subjects. The TUG test values were assessed for validity and reliability.

RESULTS: The TUG test had excellent intra- (intraclass correlation coefficient: 0.97) and interrater reliability (intraclass correlation coefficient: 0.99), with a standard error of measurement of 0.21 and 0.23 seconds, respectively. The validity of the TUG test was demonstrated by a good correlation with the Visual Analog Scale (VAS) back (Pearson’s correlation coefficient [PCC]: 0.25) and VAS (PCC: 0.29) leg pain, functional impairment (Roland-Morris Disability Index [PCC: 0.38] and Oswestry Disability Index [PCC: 0.34]), as well as with health-related quality of life (Short Form-12 Mental Component Summary score [PCC: 20.25], Short Form-12 Physical Component Summary score [PCC: 20.32], and EQ-5D [PCC: 20.28]). The upper limit of “normal” was 11.52 seconds. Mild (lower than the 33rd percentile), moderate (33rd to 66th percentiles), and severe objective functional impairment (higher than the 66th percentile) as determined by the TUG test was <13.4 seconds, 13.4 to 18.4 seconds, and >18.4 seconds, respectively.

CONCLUSION: The TUG test is a quick, easy-to-use, valid, and reliable tool to evaluate objective functional impairment in patients with lumbar degenerative disc disease. In the clinical setting, patients scoring a TUG test time of over 12 seconds can be considered to have functional impairment.

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Fractional anisotropy in patients with disproportionately enlarged subarachnoid space hydrocephalus

Fractional anisotropy in patients with disproportionately enlarged subarachnoid space hydrocephalus

Acta Neurochir (2016) 158:1495–1500

Disproportionately enlarged subarachnoid space hydrocephalus (DESH) findings on MRI were described as a prognostic factor for responsiveness to the treatment of idiopathic normal pressure hydrocephalus (iNPH). Our premise is that DESH could be associated with compression of the cerebral white matter. Microstructural changes can be identified using diffusion tensor imaging (DTI), specifically fractional anisotropy (FA). The aim of this study is to compare FA in iNPH patients with and without DESH and healthy controls.

Methods: We analysed 1.5-T MRI scans of patients fulfilling the criteria of probable or possible iNPH and positive supplementary tests before and after surgery (ventriculo-peritoneal shunt). FA was measured in the anterior and posterior limb of the internal capsule (PLIC) and in the corpus callosum. Patients were divided into the DESH and non-DESH group. These data were also compared to FA values in the control group.

Results: Twenty-seven patients and 24 healthy controls were enrolled. DESH was present in 15 patients and lacking in 12. Twenty-three iNPH patients were shunt responders (85.2 %), and 4 were non-responders (14.8 %). All patients in the DESH group were shunt responders. In the non-DESH group, eight patients were responders (66.7 %). A significant difference between the DESH and non-DESH group was found in the FA of the PLIC. The mean value of FA in the PLIC was 0.72 in the DESH group and 0.66 in the non-DESH group. After the surgery FA decreased in both groups. In the DESH iNPH group FA PLIC decreased to 0.65 and in the non-DESH iNPH group to 0.60. In the healthy controls, the mean FA in the PLIC was 0.58.

Conclusion: DESH on MRI scans is related to a higher FA in the PLIC with a decrease after the surgery. It reflects a more severe compression of the white matter than in non-DESH patients or healthy volunteers. DESH patients had better outcome than non-DESH patients. This study confirmed the importance of DESH as a supportive sign for iNPH.

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