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Daily bibliographic review of the Neurosurgery Department. La Fe University Hospital. Valencia, Spain

Risk Factors to Predict Neurologic Complications After Endovascular Treatment of Unruptured Paraclinoid Aneurysms

WORLD NEUROSURGERY 104: 89-94, AUGUST 2017

Unruptured paraclinoid aneurysms are often asymptomatic, and endovascular coiling is the main treatment. However, endovascular treatment of these lesions still leads to neurologic complications. We aimed to identify predictors of neurologic complications in these lesions.

METHODS: We retrospectively analyzed patients with unruptured paraclinoid aneurysms who were treated with endovascular coiling between January 2014 and December 2015. A neurologic complication was defined as any transient or permanent increase in the modified Rankin Scale score after aneurysm embolization. Univariate and mulitivariate logistic regression analyses were performed to assess the risk factors of neurologic complications.

RESULTS: Of the 443 unruptured paraclinoid aneurysms that were included in this study, the incidence of neurologic complications was 5.2%. Neurologic complications were highly correlated with hypertension (odds ratio [OR], 3.147; 95% confidence interval [CI], 1.217e8.138; P [ 0.018), cerebral ischemic comorbidities (OR, 3.396; 95% CI, 1.378e 8.374; P [ 0.008), and aneurysm size (OR, 7.714; 95% CI, 1.784e31.635; P < 0.001), and irregular shape (OR, 3.157; 95% CI, 1.239e8.043; P [ 0.016) in the univariate analysis. Cerebral ischemic comorbidities (OR, 2.837, 95% CI, 1.070e 7.523; P [ 0.036) and aneurysm size as dichotomous variables (OR, 7.557; 95% CI, 2.975e19.198; P < 0.001) were strongly correlated with neurologic complications in the final adjusted multivariate logistic analysis.

CONCLUSIONS: Unruptured paraclinoid aneurysms after endovascular treatments had 5.2% of neurologic complications. Cerebral ischemic comorbidities and aneurysm size were predictors of neurologic complications.

 

Complications of ventricular entry during craniotomy for brain tumor resection

J Neurosurg 127:426–432, 2017

Recent studies have demonstrated that periventricular tumor location is associated with poorer survival and that tumor location near the ventricle limits the extent of resection. This finding may relate to the perception that ventricular entry leads to further complications and thus surgeons may choose to perform less aggressive resection in these areas. However, there is little support for this view in the literature. This study seeks to determine whether ventricular entry is associated with more complications during craniotomy for brain tumor resection.

METHODS A retrospective analysis of patients who underwent craniotomy for tumor resection at Henry Ford Hospital between January 2010 and November 2012 was conducted. A total of 183 cases were reviewed with attention to operative entry into the ventricular system, postoperative use of an external ventricular drain (EVD), subdural hematoma, hydrocephalus, and symptomatic intraventricular hemorrhage (IVH).

RESULTS Patients in whom the ventricles were entered had significantly higher rates of any complication (46% vs 21%). Complications included development of subdural hygroma, subdural hematoma, intraventricular hemorrhage, subgaleal collection, wound infection, urinary tract infection/deep venous thrombosis, hydrocephalus, and ventriculoperitoneal (VP) shunt placement. Specifically, these patients had significantly higher rates of EVD placement (23% vs 1%, p < 0.001), hydrocephalus (6% vs 0%, p = 0.03), IVH (14% vs 0%, p < 0.001), infection (15% vs 5%, p = 0.04), and subgaleal collection (20% vs 4%, p < 0.001). It was also observed that VP shunt placement was only seen in cases of ventricular entry (11% vs 0%, p = 0.001) with 3 of 4 of these patients having a large ventricular entry (defined here as entry greater than a pinhole [< 3 mm] entry). Furthermore, in a subset of glioblastoma patients with and without ventricular entry, Kaplan- Meier estimates for survival demonstrated a median survival time of 329 days for ventricular entry compared with 522 days for patients with no ventricular entry (HR 1.13, 95% CI 0.65–1.96; p = 0.67).

CONCLUSIONS There are more complications associated with ventricular entry during brain tumor resection than in nonviolated ventricular systems. Better strategies for management of periventricular tumor resection should be actively sought to improve resection and survival for these patients.

 

Volume-Staged Stereotactic Radiosurgery for Intracranial Arteriovenous Malformations

Neurosurgery 80:543–550, 2017

Radiation-based treatment options of large intracranial arteriovenous malformations (AVM) must balance the likelihood of obliteration with the risk of adverse radiation effects (ARE).
OBJECTIVE: To analyze the efficacy and risks of volume-staged stereotactic radiosurgery (VS-SRS) for AVM.

METHODS: Retrospective study of 34 AVM patients having VS-SRS between 1997 and 2012. A median of 2 stages (range, 2-4) was used to treat a median AVM volume of 22.2 cm3 (range, 7.4-56.7). The median AVM margin dose was 16 Gy (range, 14-18); the median radiosurgery- based AVM score was 2.81 (range, 1.54-6.45). The median follow-up after VS-SRS was 8.2 years (range, 3-13.3).

RESULTS: Nidus obliteration was noted in 18 patients (53%) after VS-SRS. The rate of obliteration was 14% at 3 years, 54% at 5 years, and 75% at 7 years. Six patients (18%) had 11 bleeds after VS-SRS. Two patients (6%) remained neurologically stable, 2 (6%) patients had significant deficits, and 2 patients (6%) died. The actuarial risk of a first bleed after VS-SRS was 6% at 1 year, 12% at 3 years, and 19% at 7 years. Six patients (18%) underwent repeat SRS; all achieved nidus obliteration for an overall cure rate of 71%. Two patients (6%) had a permanent ARE after VS-SRS or repeat SRS.

CONCLUSION: VS-SRS permitted large volume intracranial AVM to be treated with a low rate of ARE. Further study is needed on dose escalation and decreasing the treatment volume per stage to determine if this will increase the rate of obliteration with this technique.

Minimally invasive tubular microdiscectomy for recurrent lumbar disc herniation

MIS discectomy

J Neurosurg Spine 24:48–53, 2016

The aim of the study was to investigate the safety and ef cacy of minimally invasive tubular microdiscec- tomy for the treatment of recurrent lumbar disc herniation (LDH). As opposed to endoscopic techniques, namely micro- endoscopic and endoscopic transforaminal discectomy, this microscopically assisted technique has never been used for the treatment of recurrent LDH.

Methods: Thirty consecutive patients who underwent minimally invasive tubular microdiscectomy for recurrent LDH were included in the study. The preoperative and postoperative visual analog scale (VAS) scores for pain, the clinical outcome according to modified Macnab criteria, and complications were analyzed retrospectively. The minimum follow-up was 1.5 years. Student t-test with paired samples was used for the statistical comparison of pre- and postoperative VAS scores. A p value < 0.05 was considered to be statistically significant.

Results: The mean operating time was 90 ± 35 minutes. The VAS score for leg pain was significantly reduced from 5.9 ± 2.1 preoperatively to 1.7 ± 1.3 postoperatively (p < 0.001). The overall success rate (excellent or good outcome according to Macnab criteria) was 90%. Incidental durotomy occurred in 5 patients (16.7%) without neurological consequences, CSF fistula, or negative influence to the clinical outcome. Instability occurred in 2 patients (6.7%).

Conclusions: The clinical outcome of minimally invasive tubular microdiscectomy is comparable to the reported success rates of other minimally invasive techniques. The dural tear rate is not associated to higher morbidity or worse outcome. The technique is an equally effective and safe treatment option for recurrent LDH.

Adenosine-induced transient asystole during intracranial aneurysm surgery

Adenosine-induced transient asystole

Acta Neurochir (2015) 157:1879–1886

Several flow-arrest techniques have been introduced for the treatment of complex aneurysms that cannot be treated with conventional clipping or endovascular coil embolization. Adenosine-induced transient asystole is an alternative method of flow arrest. However, given the limited number of studies that have reported on this topic, there is no consensus regarding the dose, regimen, efficacy, and potential risks of adenosine.

Method A total of 22 aneurysms in 22 different patients that underwent adenosine-induced transient asystole during aneurismal neck clipping within the past 4 years were retrospectively reviewed. Adenosine was administrated intravenously in a test-incremental manner (starting with 6–12 mg and then giving additional doses as needed) in 11 patients and in an estimated manner (pre-calculated as 0.3–0.4 mg/kg) in 11 patients.

Results Overall, the study consisted of 18 unruptured saccular aneurysms, three ruptured saccular aneurysms, and a ruptured pseudoaneurysm. Adenosine-induced transient asystole was used in cases of temporary clipping inability, wide necked aneurysm, deep-seated aneurysm, or a thin aneurysm wall. The number of administrations, dose (mg/kg in ideal body weight) and duration of asystole were 1–4 (mean, 2.3) times, 0.08–1.27 (mean, 0.36) mg/kg and 0–30 (mean 13) seconds in the test-incremental manner and 1–2 (mean, 1.09) times, 0.24–0.42 (mean, 0.34) mg/kg and 13–41 (mean, 24) seconds in the estimated manner, respectively. There was a linear relationship between the dose and the duration of asystole. Twenty out of 22 aneurysms were clipped successfully with adenosine-induced transient asystole. However, in the other two cases, additional suction decompression was required for the final clipping. Adenosine-related cardiologic complications occurred in two cases of self-limited atrial fibrillation during restoration of the cardiac rhythm.

Conclusions In our experience, adenosine-induced transient asystole was safe and helpful for satisfactory clipping of a complicated aneurysm. An estimated dose injection of adenosine was more convenient than the test-incremental method and did not result in serious cardiologic problems.

Impact of Body Mass Index on Adjacent Segment Disease After Lumbar Fusion for Degenerative Spine Disease

Impact of Body Mass Index on Adjacent Segment Disease After Lumbar Fusion for Degenerative Spine Disease

Neurosurgery 76:396–402, 2015

Adjacent segment disease is an important complication after fusion of degenerative lumbar spines. However, the role of body mass index (BMI) in adjacent segment disease has been addressed less.

OBJECTIVE: To examine the relationship between BMI and adjacent segment disease after lumbar fusion for degenerative spine diseases.

METHODS: For this retrospective study, we enrolled 190 patients undergoing lumbar fusion surgery for degeneration. BMI at admission was documented. Adjacent segment disease was defined by integration of the clinical presentations and radiographic criteria based on the morphology of the dural sac on magnetic resonance images.

RESULTS: Adjacent segment disease was identified in 13 of the 190 patients, accounting for 6.8%. The interval between surgery and diagnosis as adjacent segment disease ranged from 21 to 66 months. Five of the 13 patients required subsequent surgical intervention for clinically relevant adjacent segment disease. In the logistic regression model, BMI was a risk factor for adjacent segment disease after lumbar fusion for degenerative spine diseases (odds ratio, 1.68; 95% confidence interval, 1.27- 2.21; P < .001). Any increase of 1 mean value in BMI would increase the adjacent segment disease rate by 67.6%. The patients were subdivided into 2 groups based on BMI, and up to 11.9% of patients with BMI ≥25 kg/m2 were diagnosed as having adjacent segment disease at the last follow-up.

CONCLUSION: BMI is a risk factor for adjacent segment disease in patients undergoing lumbar fusion for degenerative spine diseases. Because BMI is clinically objective and modifiable, controlling body weight before or after surgery may provide opportunities to reduce the rate of adjacent segment disease and to improve the outcome of fusion surgery.

Major vascular injury following lateral transpsoas approach

Major vascular injury following lateral transpsoas approach

J Neurosurg Spine 21:794–798, 2014

Extreme lateral interbody fusion (XLIF) has gained popularity among spine surgeons for treating multiple conditions of the lumbar spine. In contrast to the anterior lumbar interbody fusion (ALIF) approach, the minimally invasive XLIF approach affords wide access to the lumbar disc space without an access surgeon and causes minimal tissue disruption. The XLIF approach offers many advantages over other lumbar spine approaches, with a reportedly low complication profile.

The authors describe the first fatality reported in the literature following an XLIF approach. They describe the case of a 50-year-old woman who suffered a fatal intraoperative injury to the great vessels during a lateral transpsoas approach to the L4–5 disc space.

Management of subdural hygromas associated with arachnoid cysts

Subdural hygromas associated with cysts

J Neurosurg Pediatrics 12:434–443, 2013

Arachnoid cysts may occasionally be associated with subdural hygromas. The management of these concurrent findings is controversial.

Methods. The authors reviewed their experience with arachnoid cysts and identified 8 patients with intracranial arachnoid cysts and an associated subdural hygroma. The medical records and images for these patients were also examined.

Results. In total, 8 patients presented with concurrent subdural hygroma and arachnoid cyst. Of these 8 patients, 6 presented with headaches and 4 had nausea and vomiting. Six patients had a history of trauma. One patient was treated surgically at the time of initial presentation, and 7 patients were managed without surgery. All patients experienced complete resolution of their presenting signs and symptoms.

Conclusions. Subdural hygroma may lead to symptomatic presentation for otherwise asymptomatic arachnoid cysts. The natural course of cyst-associated subdural hygromas, even when symptomatic, is generally benign, and symptom resolution can be expected in most cases. The authors suggest that symptomatic hygroma is not an absolute indication for surgical treatment and that expectant management can result in good outcomes in many cases.

Incidence and Risk Factors for Dysphagia After Anterior Cervical Fusion

ACDF

Spine 2013;38:1820–1825

Study Design. Retrospective database analysis.

Objective. To determine the national incidence, mortality, and risk factors for dysphagia associated with anterior cervical spinal fusion surgery in the United States.

Summary of Background Data. Dysphagia is a known complication associated with anterior cervical fusion (ACF). A population-based database was analyzed to characterize the incidence of dysphagia in terms of demographics, mortality, and risk factors associated with ACF.

Methods. Data from the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project were obtained from 2002 to 2009. Patients undergoing ACF for cervical myelopathy and/ or radiculopathy were identifi ed and separated into cohorts (1- to 2-level and 3 + -level fusions), and incidences of dysphagia were identifi ed. Demographics, length of stay, costs, mortality, and use of bone morphogenetic proteins (BMPs) were assessed. Statistical data were analyzed in SPSS (version 20), using the Student t test for discrete variables and the χ 2 test for categorical data. Binomial logistic regression was used to identify independent predictors of dysphagia. A P value of less than 0.001 was used to denote signifi cance.

Results. A total of 159,590 ACF cases were identified of which 139,434 were 1- to 2-level ACF and 20,156 were 3 + -level ACF. The incidence of dysphagia in the 3 + -level ACF group was double that of the 1- to 2-level ACF group (44.8 vs . 22.4 per 1000; P < 0.001). Patients with dysphagia were significantly older than patients without dysphagia ( P < 0.001). Dysphagia was more common in males undergoing 1- to 2-level ACF ( P < 0.001). BMP was used more frequently for patients with dysphagia in the 1- to 2-level ACF group (9.4% vs . 7.2% of cases; P < 0.001). Logistic regression analysis demonstrated that independent predictors for dysphagia included age ( ≥ 65 yr), male sex, 3 + -level fusion, BMP use, and preoperative patient comorbidities.

Conclusion. Dysphagia occurs twice as often after 3 + -level ACF compared with 1- to 2-level ACF. Utilization of BMP was also linked to an increased incidence of dysphagia in the 1- to 2-level ACF group. Regardless of the number of levels fused, patients experiencing dysphagia had increased age, comorbid risk factors, hospitalizations, and costs.

Level of Evidence: 3

Rigid occipitocervical fixation: indications, outcomes, and complications in the modern era

Rigid occipitocervical fixation- indications, outcomes, and complications in the modern era

J Neurosurg Spine 18:333–339, 2013

Over the past 40 years, various methods and instrumentation types have been developed for occipitocervical fixation (OCF) in the management of occipitocervical instability. This study reports indications, outcomes, and complications with rigid OCF using screw-rod and screw-plate instrumentation, which has comparatively less long-term data.

Methods. A prospectively maintained database identified 100 consecutive patients who underwent rigid OCF in a single unit over a period of 13 years. Patient demographics, clinical indications, pre- and postoperative radiographic findings, neck disability indices (NDIs), myelopathy disability indices (MDIs), visual analog scale (VAS) scores, and Ranawat scores were recorded. Complications including instrumentation failure were also documented.

Results. Underlying etiologies included rheumatoid arthritis (RA; 41%), tumor (16%), trauma (15%), congenital etiologies (14%), metabolic (6%) and inflammatory (6%) conditions, and infection (2%). The pre- and postoperative MDI and VAS scores for neck pain showed significant improvements in the RA group (MDI 64.5% vs 42.5%, p = 0.02; mean VAS 7.5 of 10 vs 3.7 of 10, p < 0.001). Improvements in MDI and NDI outcome measures were also seen in the trauma and tumor categories. Overall, there were 4 cases of instrumentation failure; all included broken rods in the stress riser region of occipitocervical rod curvature, and 1 patient also had occipital plate screw pullout. Other complications included 5 wound infections requiring wound washout, 1 vertebral artery injury (no clinical sequelae), and 1 perioperative death due to myocardial infarction.

Conclusions. Rigid OCF is a safe and effective method of managing occipitocervical instability due to a variety of causes. Outcome measures are favorable, and patients with chronically debilitating diseases such as RA may benefit in terms of improvements in neurological deficit and neck pain. The complication profile is comparable to that reported in other series of OCF in the literature, as well as to the previously used semirigid type of rod/sublaminar wire fixation.

Accuracy and complications associated with the freehand C-1 lateral mass screw fixation technique

Accuracy and complications associated with the freehand C-1 lateral mass screw fixation technique

J Neurosurg Spine 18:372–377, 2013

The aims of this study were to evaluate a large series of posterior C-1 lateral mass screws (LMSs) to determine accuracy based on CT scanning findings and to assess the perioperative complication rate related to errant screw placement.

Methods. Accuracy of screw placement was evaluated using postoperative CT scans obtained in 196 patients with atlantoaxial instability. Radiographic analysis included measurement of preoperative and postoperative CT scans to evaluate relevant anatomy and classify accuracy of instrumentation placement. Screws were graded using the following definitions: Type I, screw threads completely within the bone (ideal); Type II, less than half the diameter of the screw violates the surrounding cortex (safe); and Type III, clear violation of transverse foramen or spinal canal (unacceptable).

Results. A total of 390 C-1 LMSs were placed, but 32 screws (8.2%) were excluded from accuracy measurements because of a lack of postoperative CT scans; patients in these cases were still included in the assessment of potential clinical complications based on clinical records. Of the 358 evaluable screws with postoperative CT scanning, 85.5% of screws (Type I) were rated as being in the ideal position, 11.7% of screws (Type II) were rated as occupying a safe position, and 10 screws (2.8%) were unacceptable (Type III). Overall, 97.2% of screws were rated Type I or II. Of the 10 screws that were unacceptable on postoperative CT scans, there were no known associated neurological or vertebral artery (VA) injuries. Seven unacceptable screws erred medially into the spinal canal, and 2 patients underwent revision surgery for medial screws. In 2 patients, unilateral C-1 LMSs penetrated the C-1 anterior cortex by approximately 4 mm. Neither patient with anterior C-1 penetration had evidence of internal carotid artery or hypoglossal nerve injury. Computed tomography scanning showed partial entry of C-1 LMSs into the VA foramen of C-1 in 10 cases; no occlusion, associated aneurysm, or fistula of the VA was found. Two patients complained of postoperative occipital neuralgia. This was transient in one patient and resolved by 2 months after surgery. The second patient developed persistent neuralgia, which remained 2 years after surgery, necessitating referral to the pain service.

Conclusions. The technique for freehand C-1 LMS fixation appears to be safe and effective without intraoperative fluoroscopy guidance. Preoperative planning and determination of the ideal screw insertion point, the ideal trajectory, and screw length are the most important considerations. In addition, fewer malpositioned screws were inserted as the study progressed, suggesting a learning curve to the technique.

Analysis of lumbar plexopathies and nerve injury after lateral retroperitoneal transpsoas approach

Analysis of lumbar plexopathies and nerve injury after lateral retroperitoneal transpsoas approach

DOI: 10.3171/2012.11.SPINE12755

The minimally invasive lateral transpsoas approach has become an increasingly popular means of fusion. The most frequent complication is related to lumbar plexus nerve injuries; these can be diagnosed based on distribution of neurological deficit following the motor and/or sensory nerve injury. However, the literature has failed to provide a clinically relevant description of these complications. With accurate clinical diagnosis, spine practitioners can provide more precise prognostic and management recommendations to include observation, nerve blocks, neurodestructive procedures, medications, or surgical repair strategies. The purpose of this study was to standardize the clinical findings of lumbar plexopathies and nerve injuries associated with minimally invasive lateral retroperitoneal transpsoas lumbar fusion.

Methods. A thorough literature search of the MEDLINE database up to June 2012 was performed to identify studies that reported lumbar plexus and nerve injuries after the minimally invasive lateral retroperitoneal transpsoas approach. Included studies were assessed for described neurological deficits postoperatively. Studies that did attempt to describe nerve-related complications clinically were excluded. A clinically relevant assessment of lumbar plexus nerve injury was derived to standardize early diagnosis and outline prognostic implications.

Results. A total of 18 studies were selected with a total of 2310 patients; 304 patients were reported to have possible plexus-related complications. The incidence of documented nerve and/or root injury and abdominal paresis ranged from 0% to 3.4% and 4.2%, respectively. Motor weakness ranged from 0.7% to 33.6%. Sensory complications ranged from 0% to 75%. A lack of consistency in the descriptions of the lumbar plexopathies and/or nerve injuries as well as a lack of diagnostic paradigms was noted across studies reviewed. Sensory dermal zones were established and a standardized approach was proposed.

Conclusions. There is underreporting of postoperative lumbar plexus nerve injury and a lack of standardization of clinical findings of neural complications related to the minimally invasive lateral retroperitoneal transpsoas approach. The authors provide a diagnostic paradigm that allows for an efficient and accurate classification of postoperative lumbar plexopathies and nerve injuries.

Short circuit in deep brain stimulation

J Neurosurg 117:955–961, 2012

The authors undertook this study to investigate the incidence, cause, and clinical influence of short circuits in patients treated with deep brain stimulation (DBS).

Methods. After the incidental identification of a short circuit during routine follow-up, the authors initiated a policy at their institution of routinely evaluating both therapeutic impedance and system impendence at every outpatient DBS follow-up visit, irrespective of the presence of symptoms suggesting possible system malfunction. This study represents a report of their findings after 1 year of this policy.

Results. Implanted DBS leads exhibiting short circuits were identified in 7 patients (8.9% of the patients seen for outpatient follow-up examinations during the 12-month study period). The mean duration from DBS lead implantation to the discovery of the short circuit was 64.7 months. The symptoms revealing short circuits included the wearing off of therapeutic effect, apraxia of eyelid opening, or dysarthria in 6 patients with Parkinson disease (PD), and dystonia deterioration in 1 patient with generalized dystonia. All DBS leads with short circuits had been anchored to the cranium using titanium miniplates. Altering electrode settings resulted in clinical improvement in the 2 PD cases in which patients had specific symptoms of short circuits (2.5%) but not in the other 4 cases. The patient with dystonia underwent repositioning and replacement of a lead because the previous lead was located too anteriorly, but did not experience symptom improvement.

Conclusions. In contrast to the sudden loss of clinical efficacy of DBS caused by an open circuit, short circuits may arise due to a gradual decrease in impedance, causing the insidious development of neurological symptoms via limited or extended potential fields as well as shortened battery longevity. The incidence of short circuits in DBS may be higher than previously thought, especially in cases in which DBS leads are anchored with miniplates. The circuit impedance of DBS should be routinely checked, even after a long history of DBS therapy, especially in cases of miniplate anchoring.

Surgery for vestibular schwannomas: a systematic review of complications by approach

Neurosurg Focus 33 (3):E14, 2012

Various studies report outcomes of vestibular schwannoma (VS) surgery, but few studies have compared outcomes across the various approaches. The authors conducted a systematic review of the available data on VS surgery, comparing the different approaches and their associated complications.

Methods. MEDLINE searches were conducted to collect studies that reported information on patients undergoing VS surgery. The authors set inclusion criteria for such studies, including the availability of follow-up data for at least 3 months, inclusion of preoperative and postoperative audiometric data, intraoperative monitoring, and reporting of results using established and standardized metrics. Data were collected on hearing loss, facial nerve dysfunction, persistent postoperative headache, CSF leak, operative mortality, residual tumor, tumor recurrence, cranial nerve (CN) dysfunction involving nerves other than CN VII or VIII, and other neurological complications. The authors reviewed data from 35 studies pertaining to 5064 patients who had undergone VS surgery.

Results. The analyses for hearing loss and facial nerve dysfunction were stratified into the following tumor categories: intracanalicular (IC), size (extrameatal diameter) < 1.5 cm, size 1.5–3.0 cm, and size > 3.0 cm. The middle cranial fossa approach was found to be superior to the retrosigmoid approach for hearing preservation in patients with tumors < 1.5 cm (hearing loss in 43.6% vs 64.3%, p < 0.001). All other size categories showed no significant difference between middle cranial fossa and retrosigmoid approaches with respect to hearing loss. The retrosigmoid approach was associated with significantly less facial nerve dysfunction in patients with IC tumors than the middle cranial fossa method was; however, neither differed significantly from the translabyrinthine corridor (4%, 16.7%, 0%, respectively, p < 0.001). The middle cranial fossa approach differed significantly from the translabyrinthine approach for patients with tumors < 1.5 cm, whereas neither differed from the retrosigmoid approach (3.3%, 11.5%, and 7.2%, respectively, p = 0.001). The retrosigmoid approach involved less facial nerve dysfunction than the middle cranial fossa or translabyrinthine approaches for tumors 1.5–3.0 cm (6.1%, 17.3%, and 15.8%, respectively; p < 0.001). The retrosigmoid approach was also superior to the translabyrinthine approach for tumors > 3.0 cm (30.2% vs 42.5%, respectively, p < 0.001). Postoperative headache was significantly more likely after the retrosigmoid approach than after the translabyrinthine approach, but neither differed significantly from the middle cranial fossa approach (17.3%, 0%, and 8%, respectively; p < 0.001). The incidence of CSF leak was significantly greater after the retrosigmoid approach than after either the middle cranial fossa or translabyrinthine approaches (10.3%, 5.3%, 7.1%; p = 0.001). The incidences of residual tumor, mortality, major non-CN complications, residual tumor, tumor recurrence, and dysfunction of other cranial nerves were not significantly different across the approaches.

Conclusions. The middle cranial fossa approach seems safest for hearing preservation in patients with smaller tumors. Based on the data, the retrosigmoid approach seems to be the most versatile corridor for facial nerve preservation for most tumor sizes, but it is associated with a higher risk of postoperative pain and CSF fistula. The translabyrinthine approach is associated with complete hearing loss but may be useful for patients with large tumors and poor preoperative hearing.

Technical nuances of resection of giant (> 5 cm) vestibular schwannomas: pearls for success

Neurosurg Focus 33 (3):E15, 2012

Removal of vestibular schwannomas (VSs, or acoustic neuromas) remains one of the most challenging operations in neurosurgery. Giant or huge tumors (> 5 cm) heighten these challenges, and technical nuances play a special role in maximizing tumor resection while minimizing complications.

In this article, the senior author describes his technical experience with microsurgical excision of giant VSs. The accompanying video further illustrates these details.

 

Surgery for vestibular schwannomas: a systematic review of complications by approach

Neurosurg Focus 33 (3):E14, 2012

Various studies report outcomes of vestibular schwannoma (VS) surgery, but few studies have compared outcomes across the various approaches. The authors conducted a systematic review of the available data on VS surgery, comparing the different approaches and their associated complications.

Methods. MEDLINE searches were conducted to collect studies that reported information on patients undergoing VS surgery. The authors set inclusion criteria for such studies, including the availability of follow-up data for at least 3 months, inclusion of preoperative and postoperative audiometric data, intraoperative monitoring, and reporting of results using established and standardized metrics. Data were collected on hearing loss, facial nerve dysfunction, persistent postoperative headache, CSF leak, operative mortality, residual tumor, tumor recurrence, cranial nerve (CN) dysfunction involving nerves other than CN VII or VIII, and other neurological complications. The authors reviewed data from 35 studies pertaining to 5064 patients who had undergone VS surgery.

Results. The analyses for hearing loss and facial nerve dysfunction were stratified into the following tumor categories: intracanalicular (IC), size (extrameatal diameter) < 1.5 cm, size 1.5–3.0 cm, and size > 3.0 cm. The middle cranial fossa approach was found to be superior to the retrosigmoid approach for hearing preservation in patients with tumors < 1.5 cm (hearing loss in 43.6% vs 64.3%, p < 0.001). All other size categories showed no significant difference between middle cranial fossa and retrosigmoid approaches with respect to hearing loss. The retrosigmoid approach was associated with significantly less facial nerve dysfunction in patients with IC tumors than the middle cranial fossa method was; however, neither differed significantly from the translabyrinthine corridor (4%, 16.7%, 0%, respectively, p < 0.001). The middle cranial fossa approach differed significantly from the translabyrinthine approach for patients with tumors < 1.5 cm, whereas neither differed from the retrosigmoid approach (3.3%, 11.5%, and 7.2%, respectively, p = 0.001). The retrosigmoid approach involved less facial nerve dysfunction than the middle cranial fossa or translabyrinthine approaches for tumors 1.5–3.0 cm (6.1%, 17.3%, and 15.8%, respectively; p < 0.001). The retrosigmoid approach was also superior to the translabyrinthine approach for tumors > 3.0 cm (30.2% vs 42.5%, respectively, p < 0.001). Postoperative headache was significantly more likely after the retrosigmoid approach than after the translabyrinthine approach, but neither differed significantly from the middle cranial fossa approach (17.3%, 0%, and 8%, respectively; p < 0.001). The incidence of CSF leak was significantly greater after the retrosigmoid approach than after either the middle cranial fossa or translabyrinthine approaches (10.3%, 5.3%, 7.1%; p = 0.001). The incidences of residual tumor, mortality, major non-CN complications, residual tumor, tumor recurrence, and dysfunction of other cranial nerves were not significantly different across the approaches.

Conclusions. The middle cranial fossa approach seems safest for hearing preservation in patients with smaller tumors. Based on the data, the retrosigmoid approach seems to be the most versatile corridor for facial nerve preservation for most tumor sizes, but it is associated with a higher risk of postoperative pain and CSF fistula. The translabyrinthine approach is associated with complete hearing loss but may be useful for patients with large tumors and poor preoperative hearing.

Perioperative mortality after lumbar spinal fusion surgery: an analysis of epidemiology and risk factors

Eur Spine J (2012) 21:1633–1639 DOI 10.1007/s00586-012-2298-8

Study design Analysis of the Nationwide Inpatient Sample (NIS) from 1998 to 2008.

Objective To analyze the most recent available and nationally representative data for risk factors contributing to in-hospital mortality after primary lumbar spine fusion.

Summary of background data The total number of lumbar spine fusion surgeries has increased dramatically over the past decades. While the field of spine fusion surgery remains highly dynamic with changes in perioperative care constantly affecting patient care, recent data affecting rates and risk for perioperative mortality remain very limited.

Methods We obtained the NIS from the Hospital cost and utilization project. The impact of patient and health care system related demographics, including various comorbidities as well as postoperative complications on the outcome of in-hospital mortality after spine fusion were studied. Furthermore, we analyzed the timing of in-hospital mortality.

Results An estimated total of 1,288,496 primary posterior lumbar spine fusion procedures were performed in the US between 1998 and 2008. The average mortality rate for lumbar spine fusion surgery was 0.2 %. Independent risk factors for in-hospital mortality included advanced age, male gender, large hospital size, and emergency admission. Comorbidities associated with the highest in-hospital mortality after lumbar spine fusion surgery were coagulopathy, metastatic cancer, congestive heart failure and renal disease. Most lethal complications were cerebrovascular events, sepsis and pulmonary embolism. Furthermore, we demonstrated that the timing of death occurred relatively early in the in-hospital period with over half of fatalities occurring by postoperative day 9.

Conclusion This study provides nationally representative information on risk factors for and timing of perioperative mortality after primary lumbar spine fusion surgery. These data can be used to assess risk for this event and to develop targeted intervention to decrease such risk.

Anterior Cervical Reconstruction With Pedicle Screws After a 4-Level Corpectomy

Spine 2012 ; 37 : E927 – E930

Anterior reconstruction after multilevel corpectomy is a challenging technique, and there are many reports on its complications. Graft dislodgement is one of the major complications after long cervical fusion. The main cause of failure seems to be a lack of stability in the conventional reconstruction technique. However, pedicle screws for posterior cervical reconstruction show remarkable stability. We describe a new technique of anterior cervical reconstruction with pedicle screws and fibular strut grafting.

Methods. Seven patients with multilevel cervical myelopathy were treated with this new reconstruction technique after a 4-level corpectomy. We describe this new technique and review the patients’ clinical history, results of radiographical imaging, and outcomes. Clinical outcomes were assessed preoperatively and at 3 months postoperatively. Postoperative radiographs were assessed 3 months and 6 months postoperatively.

Results. The mean operative time was 182 minutes and the mean blood loss was 271 mL. The average Japanese Orthopaedic Association score for cervical myelopathy improved from 11.5 points preoperatively to 14.5 points 3 months postoperatively. No patients experienced major complications, such as neurological deterioration, infection, or massive blood loss. There was no case of reconstruction failure, graft dislodgement, migration, or screw displacement.

Conclusion. To our knowledge, this is the first description of an anterior cervical reconstruction approach, using pedicle screws and fibular strut grafting after a 4-level corpectomy. It is likely that this technique will result in better clinical outcomes with fewer complications in the treatment of patients with multilevel cervical myelopathy.

Complications associated with the surgical treatment of cervical spondylotic myelopathy

J Neurosurg Spine 16:425–432, 2012. (http://thejns.org/doi/abs/10.3171/ 2012.1.SPINE11467) 

Rates of complications associated with the surgical treatment of cervical spondylotic myelopathy (CSM) are not clear. Appreciating these risks is important for patient counseling and quality improvement. The authors sought to assess the rates of and risk factors associated with perioperative and delayed complications associated with the surgical treatment of CSM.

Methods. Data from the AOSpine North America Cervical Spondylotic Myelopathy Study, a prospective, multicenter study, were analyzed. Outcomes data, including adverse events, were collected in a standardized manner and externally monitored. Rates of perioperative complications (within 30 days of surgery) and delayed complications (31 days to 2 years following surgery) were tabulated and stratified based on clinical factors.

Results. The study enrolled 302 patients (mean age 57 years, range 29–86) years. Of 332 reported adverse events, 73 were classified as perioperative complications (25 major and 48 minor) in 47 patients (overall perioperative complication rate of 15.6%). The most common perioperative complications included minor cardiopulmonary events (3.0%), dysphagia (3.0%), and superficial wound infection (2.3%). Perioperative worsening of myelopathy was reported in 4 patients (1.3%). Based on 275 patients who completed 2 years of follow-up, there were 14 delayed complications (8 minor, 6 major) in 12 patients, for an overall delayed complication rate of 4.4%. Of patients treated with anterior-only (n = 176), posterior-only (n = 107), and combined anterior-posterior (n = 19) procedures, 11%, 19%, and 37%, respectively, had 1 or more perioperative complications. Compared with anterior-only approaches, posterior-only approaches had a higher rate of wound infection (0.6% vs 4.7%, p = 0.030). Dysphagia was more common with combined anterior-posterior procedures (21.1%) compared with anterior-only procedures (2.3%) or posterior-only procedures (0.9%) (p < 0.001). The incidence of C-5 radiculopathy was not associated with the surgical approach (p = 0.8). The occurrence of perioperative complications was associated with increased age (p = 0.006), combined anterior-posterior procedures (p = 0.016), increased operative time (p = 0.009), and increased operative blood loss (p = 0.005), but it was not associated with comorbidity score, body mass index, modified Japanese Orthopaedic Association score, smoking status, anterior-only versus posterior-only approach, or specific procedures. Multivariate analysis of factors associated with minor or major complications identified age (OR 1.029, 95% CI 1.002–1.057, p = 0.035) and operative time (OR 1.005, 95% CI 1.002–1.008, p = 0.001). Multivariate analysis of factors associated with major complications identified age (OR 1.054, 95% CI 1.015–1.094, p = 0.006) and combined anterior-posterior procedures (OR 5.297, 95% CI 1.626–17.256, p = 0.006).

Conclusions. For the surgical treatment of CSM, the vast majority of complications were treatable and without long-term impact. Multivariate factors associated with an increased risk of complications include greater age, increased operative time, and use of combined anterior-posterior procedures.

Mini-open lateral approach for thoracic disc herniation

J Neurosurg Spine 16:264–279, 2012. DOI: 10.3171/2011.10.SPINE11291

Symptomatic herniated thoracic discs remain a surgical challenge and historically have been associated with significant complications. While neurological outcomes have improved with the abandonment of decompressive laminectomy, the attempt to minimize surgical complications and associated morbidities continues through less invasive approaches. Many of these techniques, such as thoracoscopy, have not been widely adopted due to technical difficulties. The current study was performed to examine the safety and early results of a minimally invasive lateral approach for symptomatic thoracic herniated intervertebral discs.

Methods. Sixty patients from 5 institutions were treated using a mini-open lateral approach for 75 symptomatic thoracic herniated discs with or without calcification. The mean age was 57.9 years (range 23–80 years), and 53.3% of the patients were male. Treatment levels ranged from T4–5 to T11–12, with 1–3 levels being treated (mean 1.3 levels). The most common levels treated were T11–12 (14 cases [18.7%]), T7–8 (12 cases [16%]), and T8–9 (12 cases [16%]). Symptoms included myelopathy in 70% of cases, radiculopathy in 51.7%, axial back pain in 76.7%, and bladder and/or bowel dysfunction in 26.7%. Instrumentation included an interbody spacer in all but 6 cases (10%). Supplemental internal fixation included anterolateral plating in 33.3% of cases and pedicle screws in 10%; there was no supplemental internal fixation in 56.7% of cases. Follow-up ranged from 0.5 to 24 months (mean 11.0 months).

Results. The median operating time, estimated blood loss, and length of stay were 182 minutes, 290 ml, and 5.0 days, respectively. Four major complications occurred (6.7%): pneumonia in 1 patient (1.7%); extrapleural free air in 1 patient (1.7%), treated with chest tube placement; new lower-extremity weakness in 1 patient (1.7%); and wound infection in posterior instrumentation in 1 patient (1.7%). Reoperations occurred in 3 cases (5%): one for posterior reexploration, one for infection in posterior instrumentation, and one for removal of symptomatic residual disc material. Back pain, measured using the visual analog scale, improved 60% from the preoperative score to the last follow-up, that is, from 7.8 to 3.1. Excellent or good overall outcomes were achieved in 80% of the patients, a fair or unchanged outcome resulted in 15%, and a poor outcome occurred in 5%. Moreover, myelopathy, radiculopathy, axial back pain, and bladder and/or bowel dysfunction improved in 83.3%, 87.0%, 91.1%, and 87.5% of cases, respectively.

Conclusions. The authors’ early experience with a large multicenter series suggested that the minimally invasive lateral approach is a safe, reproducible, and efficacious procedure for achieving adequate decompression in thoracic disc herniations in a less invasive manner than conventional surgical techniques and without the use of endoscopes. Symptom resolution was achieved at similar rates using this approach as compared with the most efficacious techniques in the literature, and with fewer complications in most circumstances.

Neurosurgery Department. “La Fe” University Hospital. Valencia, Spain

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