Failure of Internal Cerebrospinal Fluid Shunt: A Systematic Review and Meta-Analysis of the Overall Prevalence in Adults

World Neurosurg. (2023) 169:20-30

Reported rates of failures of internal cerebrospinal fluid shunt (ICSFS) vary greatly from less than 5% to more than 50% and no meta-analysis to assess the overall prevalence has been performed. We estimated the failure rate after ICSFS insertion and searched for associated factors.

METHODS: Six databases were searched from January 1990 to February 2022. Only original articles reporting the rate of adult shunt failure were included. Random-effects meta-analysis with a generalized linear mixed model method and logit transformation was used to compute the overall failure prevalence. Subgroup analysis and meta-regression were implemented to search for associated factors.

RESULTS: Of 1763 identified articles, 46 were selected, comprising 70,859 ICSFS implantations and 13,603 shunt failures, suggesting an accumulated incidence of 19.2%. However, the calculated pooled prevalence value and its 95% confidence interval (CI) were 22.7% (95% CI, 19.8e5.8). The CI of the different estimates did not overlap, indicating a strong heterogeneity confirmed by a high I 2 of 97.5% (95% CI, 97.1e97.8; P < 0.001; s 2 [ 0.3). Ninety-five percent prediction interval of shunt failure prevalence ranged from 8.75% to 47.36%. A meta-regression of prevalence of publication found a barely significant decreasing failure rate of about 2% per year (e2.11; 95% CI, e4.02 to e0.2; P [ 0.031).

CONCLUSIONS: Despite being a simple neurosurgical procedure, ICSFS insertion has one of the highest risk of complications, with failure prevalence involving more than 1 patient of 5. Nonetheless, all efforts to lower this high level of shunt failure seem to be effective.

Older meningioma patients: a retrospective population‐based study of risk factors for morbidity and mortality after neurosurgery

Acta Neurochirurgica (2022) 164:2987–2997

Meningioma is the most common primary CNS tumour. Most meningiomas are benign, and most patients are 65 years or older. Surgery is usually the primary treatment option. Most prior studies on early surgical outcomes in older patients with meningioma are small, and there is a lack of larger population-based studies to guide clinical decision-making. We aimed to explore the risks for perioperative mortality and morbidity in older patients with meningioma and to investigate changes in surgical incidence over time.

Methods In this retrospective population-based study on patients in Sweden, 65 years or older with surgery 1999–2017 for meningioma, we used data from the Swedish Brain Tumour Registry. We analysed factors contributing to perioperative mor- tality and morbidity and used official demographic data to calculate yearly incidence of surgical procedures for meningioma.

Results Thefinal study cohort included 1676 patients with a 3.1% perioperative mortality and a 37.6% perioperative morbidity. In multivariate analysis, higher age showed a statistically significant association with higher perioperative mortality, whereas larger tumour size and having preoperative symptoms were associated with higher perioperative morbidity. A numerical increased rate of surgical interventions after 2012 was observed, without evidence of worsening short-term surgical outcomes.

Conclusions Higher mortality with increased age and higher morbidity risk in larger and/or symptomatic tumours imply a possible benefit from considering surgery in selected older patients with a growing meningioma before the development of tumour-related symptoms. This study further underlines the need for a standardized method of reporting and classifying complications from neurosurgery.

Subsidence after lateral lumbar interbody fusion using a 3D-printed porous titanium interbody cage

J Neurosurg Spine 37:663–669, 2022

Cage subsidence is a well-known phenomenon after lateral lumbar interbody fusion (LLIF), occurring in 10%–20% of cases. A 3D-printed porous titanium (pTi) cage has a stiffness that mimics the modulus of elasticity of native vertebrae, which reduces stress at the bone-hardware interface, lowering the risk of subsidence. In this study, the authors evaluated their institutional rate of subsidence and resultant reoperation in patients who underwent LLIF using a 3D-printed pTi interbody cage.

METHODS This is a retrospective case series of consecutive adult patients who underwent LLIF using pTi cages from 2018 to 2020. Demographic and clinical characteristics including age, sex, bone mineral density, smoking status, diabetes, steroid use, number of fusion levels, posterior instrumentation, and graft size were collected. The Marchi subsidence grade was determined at the time of last follow-up. Outcome measures of interest were subsidence and resultant reoperation. Univariable logistic regression analysis was performed to assess the extent to which clinical and operative characteristics were associated with Marchi grade I–III subsidence. Significance was assessed at p < 0.05.

RESULTS Fifty-five patients (38 with degenerative disc disease and 17 with adult spinal deformity) were treated with 97 pTi interbody cages with a mean follow-up of 18 months. The mean age was 63.6 ± 10.1 years, 60% of patients were female, and 36% of patients had osteopenia or osteoporosis. Patients most commonly underwent single-level LLIF (58.2%). Sixteen patients (29.1%) had posterior instrumentation. The subsidence grade distribution was as follows: 89 (92%) grade 0, 5 (5%) grade I, 2 (2%) grade II, and 1 (1%) grade III. No patients who were active or prior smokers and no patients with posterior instrumentation experienced graft subsidence. No clinical or operative characteristics were significantly associated with graft subsidence. One patient (1.8%) required reoperation because of subsidence.

CONCLUSIONS In this institutional case series, subsidence of pTi intervertebral cages after LLIF occurred in 8% of operated levels, 3% of which were grade II or III. Only 1 patient required reoperation. These reported rates are lower than those reported for polyetheretherketone implants. Further studies are necessary to compare the impact of these cage materials on subsidence after LLIF.

Management of severe intraoperative hemorrhage during intraventricular neuroendoscopic procedures: the dry field technique

Acta Neurochirurgica (2022) 164:2551–2557

Neuroendoscopic procedures inside the ventricular system always bear the risk for an unexpected intraoperative hemorrhage with potentially devastating consequences. The authors present here their experience, and a stage-to-stage guide for the endoscopic management of intraoperative hemorrhages.

Methods A step-by-step guide for the management to gain control of and stop the bleeding is described including a grading system. More advanced techniques are presented in cases examples.

Conclusion Most of intraoperative hemorrhages can be controlled by constant irrigation and coagulation. More advanced techniques can be applied quickly and easily to ensure control of the hemorrhages and avoid the need for a microsurgical conversion.

Complications associated with early cranioplasty for patients with traumatic brain injury

J Neurosurg 137:776–781, 2022

Cranioplasty is a technically simple procedure, although one with potentially high rates of complications. The ideal timing of cranioplasty should minimize the risk of complications, but research investigating cranioplasty timing and risk of complications has generated diverse findings. Previous studies have included mixed populations of patients undergoing cranioplasty following decompression for traumatic, vascular, and other cerebral insults, making results challenging to interpret. The objective of the current study was to examine rates of complications associated with cranioplasty, specifically for patients with traumatic brain injury (TBI) receiving this procedure at the authors’ high-volume level 1 trauma center over a 25-year time period.

METHODS A single-institution retrospective review was conducted of patients undergoing cranioplasty after decompression for trauma. Patients were identified and clinical and demographic variables obtained from 2 neurotrauma databases. Patients were categorized into 3 groups based on timing of cranioplasty: early (≤ 90 days after craniectomy), intermediate (91–180 days after craniectomy), and late (> 180 days after craniectomy). In addition, a subgroup analysis of complications in patients with TBI associated with ultra-early cranioplasty (< 42 days, or 6 weeks, after craniectomy) was performed.

RESULTS Of 435 patients identified, 141 patients underwent early cranioplasty, 187 patients received intermediate cranioplasty, and 107 patients underwent late cranioplasty. A total of 54 patients underwent ultra-early cranioplasty. Among the total cohort, the mean rate of postoperative hydrocephalus was 2.8%, the rate of seizure was 4.6%, the rate of postoperative hematoma was 3.4%, and the rate of infection was 6.0%. The total complication rate for the entire population was 16.8%. There was no significant difference in complications between any of the 3 groups. No significant differences in postoperative complications were found comparing the ultra-early cranioplasty group with all other patients combined.

CONCLUSIONS In this cohort of patients with TBI, early cranioplasty, including ultra-early procedures, was not associated with higher rates of complications. Early cranioplasty may confer benefits such as shorter or fewer hospitalizations, decreased financial burden, and overall improved recovery, and should be considered based on patient-specific factors.


Early mobilization versus bed rest for incidental durotomy

J Neurosurg Spine 37:460–465, 2022

The aim of this study was to assess whether flat bed rest for > 24 hours after an incidental durotomy improves patient outcome or is a risk factor for medical and wound complications and longer hospital stay.

METHODS Medical records of consecutive patients undergoing thoracic and lumbar decompression procedures from 2010 to 2020 were reviewed. Operative notes and progress notes were reviewed and searched to identify patients in whom incidental durotomies occurred. The need for revision surgery related to CSF leak or wound infection was recorded. The duration of bed rest, length of hospital stay, and complications (pulmonary, gastrointestinal, urinary, and wound) were recorded. The rates of complications were compared with regard to the duration of bed rest (≤ 24 hours vs > 24 hours).

RESULTS A total of 420 incidental durotomies were identified, indicating a rate of 6.7% in the patient population. Of the 420 patients, 361 underwent primary repair of the dura; 254 patients were prescribed bed rest ≤ 24 hours, and 107 patients were prescribed bed rest > 24 hours. There was no statistically significant difference in the need for revision surgery (7.87% vs 8.41%, p = 0.86) between the two groups, but wound complications were increased in the prolonged bed rest group (8.66% vs 15.89%, p = 0.043). The average length of stay for patients with bed rest ≤ 24 hours was 4.47 ± 3.64 days versus 7.24 ± 4.23 days for patients with bed rest > 24 hours (p < 0.0001). There was a statistically significant increase in the frequency of ileus, urinary retention, urinary tract infections, pulmonary issues, and altered mental status in the group with prolonged bed rest after an incidental durotomy. The relative risk of complications in the group with bed rest ≤ 24 hours was 50% less than the group with > 24 hours of bed rest (RR 0.5, 95% CI 0.39–0.62; p < 0.0001).

CONCLUSIONS In this retrospective study, the rate of revision surgery was not higher in patients with durotomy who underwent immediate mobilization, and medical complications were significantly decreased. Flat bed rest > 24 hours following incidental durotomy was associated with increased length of stay and increased rate of medical complications. After primary repair of an incidental durotomy, flat bed rest may not be necessary and appears to be associated with higher costs and complications.


Long-Term Risks of Hemorrhage and Adverse Radiation Effects of Stereotactic Radiosurgery for Brain Arteriovenous Malformations

Neurosurgery 90:784–792, 2022

The information about long-term risks of hemorrhage and late adverse radiation effects (AREs) after stereotactic radiosurgery for brain arteriovenous malformations (AVMs) is lacking.

OBJECTIVE: To evaluate the long-term risks of hemorrhage and late ARE rates in patients with AVM treated with Gamma Knife surgery (GKS). METHODS: We examined 1249 patients with AVM treated with GKS. The Spetzler–Martin grade was I in 313 patients (25%), II in 394 (32%), III in 458 (37%), and IV/V in 84 (7%). The median treatment volume was 2.5 cm3, and the median marginal dose was 20 Gy.

RESULTS: The median follow-up period was 61 months. The 5- and 10-year nidus obliteration rates were 63% and 82%, respectively. The 5- and 10-year cumulative hemorrhage rates were 7% and 10%, respectively. The annual hemorrhage rate was 1.5% for the first 5 years post-GKS, which decreased to 0.5% thereafter. During the follow-up period, 42 symptomatic cyst formations/ chronic encapsulated hematomas ([CFs/CEHs], 3%) and 3 radiation-induced tumors (0.2%) were observed. The 10- and 15-year cumulative CF/CEH rates were 3.7% and 9.4%, respectively.

CONCLUSION: GKS is associated with reduced hemorrhage risk and high nidus obliteration rates in patients with AVM. The incidence of late AREs tended to increase over time. The most common ARE was CF/CEH, which can be safely removed; however, careful attention should be paid to the long-term development of fatal radiation-induced tumors.

Lumbar decompression surgery for cauda equina syndrome — comparison of complication rates between daytime and overnight operating

Acta Neurochirurgica (2022) 164:1203–1208

Purpose To investigate the incidence of complications from lumbar decompression ± discectomy surgery for cauda equina syndrome (CES), assessing whether time of day is associated with a change in the incidence of complications.

Methods Electronic clinical and operative notes for all lumbar decompression operations undertaken at our institution for CES over a 2-year time period were retrospectively reviewed. “Overnight” surgery was defined as any surgery occurring between 18:00 and 08:00 on any day. Clinicopathological characteristics, surgical technique, and peri/post-operative complications were recorded. Multivariable logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals.

Results A total of 81 lumbar decompression operations were performed in the 2-year period and analysed. A total of 29 (36%) operations occurred overnight. Complete CES (CESR) was seen in 13 cases (16%) in total, 7 of whom underwent surgery during the day. Exactly 27 complications occurred in 24 (30%) patients. The most frequently occurring complication was a dural tear (n = 21, 26%), followed by post-operative haematoma, infection, and residual disc. Complication rates in the CESR cohort (54%) were significantly greater than in the CES incomplete (CESI) cohort (25%) (p = 0.04). On multivariable analysis, overnight surgery was independently associated with a significantly increased complication rate (OR 2.83, CI 1.02–7.89).

Conclusions Lumbar decompressions performed overnight for CES were more than twice as likely to suffer a complication, in comparison to those performed within daytime hours. Our study suggests that out-of-hours operating, particularly at night, must be clinically justified and should not be influenced by day-time operating capacity.

Incidence of major and minor vascular injuries during lateral access lumbar interbody fusion procedures

Neurosurgical Review (2022) 45:1275–1289

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications.

We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms “vascular injury” and “lateral lumbar surgery.”

Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0–15.4% and minor vascular injury occurred in 0–6% of lateral lumbar fusions.

The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

Risk of tract recurrence with stereotactic biopsy of brain metastases

J Neurosurg 136:1045–1051, 2022

Stereotactic biopsy is increasingly performed on brain metastases (BrMs) as improving cancer outcomes drive aggressive multimodality treatment, including laser interstitial thermal therapy (LITT). However, the tract recurrence (TR) risk is poorly defined in an era defined by focused-irradiation paradigms. As such, the authors aimed to define indications and adjuvant therapies for this procedure and evaluate the BrM-biopsy TR rate.

METHODS In a single-center retrospective review, the authors identified stereotactic BrM biopsies performed from 2002 to 2020. Surgical indications, radiographic characteristics, stereotactic planning, dosimetry, pre- and postoperative CNS-directed and systemic treatments, and clinical courses were collected. Recurrence was evaluated using RANO-BM (Response Assessment in Neuro-Oncology Brain Metastases) criteria.

RESULTS In total, 499 patients underwent stereotactic intracranial biopsy for any diagnosis, of whom 25 patients (5.0%) underwent biopsy for pathologically confirmed viable BrM, a proportion that increased over the time period studied. Twelve of the 25 BrM patients had ≥ 3 months of radiographic follow-up, of whom 6 patients (50%) developed new metastatic growth along the tract at a median of 5.0 months post-biopsy (range 2.3–17.1 months). All of the TR cases had undergone pre- or early post-biopsy stereotactic radiosurgery (SRS), and 3 had also undergone LITT at the time of initial biopsy. TRs were treated with resection, reirradiation, or observation/systemic therapy.

CONCLUSIONS In this study the authors identified a nontrivial, higher than previously described rate of BrM-biopsy tract recurrence, which often required additional surgery or radiation and justified close radiographic surveillance. As BrMs are commonly treated with SRS limited to enhancing tumor margins, consideration should be made, in cases lacking CNS-active systemic treatments, to include biopsy tracts in adjuvant radiation plans where feasible.

Severity, timeline, and management of complications after stereotactic brain biopsy

J Neurosurg 136:867–876, 2022

The literature shows discrepancies in stereotactic brain biopsy complication rates, severities, and outcomes. Little is known about the timeline of postbiopsy complications. This study aimed to analyze 1) complications following brain biopsies, using a graded severity scale, and 2) a timeline of complication occurrence. The secondary objectives were to determine factors associated with an increased risk of complications and to assess complication related management and extra costs.

METHODS The authors retrospectively examined 1500 consecutive stereotactic brain biopsies performed in adult patients at their tertiary medical center between April 2009 and April 2019.

RESULTS Three hundred eighty-one biopsies (25.4%) were followed by a complication, including 88.2% of asymptomatic hemorrhages. Symptomatic complications involved 3.0% of the biopsies, and 0.8% of the biopsies were fatal. The severity grading scale had a 97.6% interobserver reproducibility. Twenty-three (51.1%) of the 45 symptomatic complications occurred within the 1st hour following the biopsy, while 75.6% occurred within the first 6 hours. Age ≥ 65 years, second biopsy procedures, gadolinium-enhanced lesions, glioblastomas, and lymphomas were predictors of biopsy-related complications. Brainstem biopsy-targeted lesions and cerebral toxoplasmosis were predictive of mortality. Asymptomatic hemorrhage was associated with delayed (> 6 hours) symptomatic complications. Symptomatic complications led to extended hospitalization in 86.7% of patients. The average extra cost for management of a patient with postbiopsy symptomatic complication was $35,702.

CONCLUSIONS Symptomatic complications from brain biopsies are infrequent but associated with substantial adverse effects and cost implications for the healthcare system. The use of a severity grading scale, as the authors propose in this article, helps to classify complications according to the therapeutic consequences and the patient’s outcome. Because this study indicates that most complications occur within the first few hours following the biopsy, postbiopsy monitoring can be tailored accordingly. The authors therefore recommend systematic monitoring for 2 hours in the recovery unit and a CT scan 2 hours after the end of the biopsy procedure. In addition, they propose a modern algorithm for optimal postoperative management of patients undergoing stereotactic biopsy.

Complications of degenerative lumbar spondylolisthesis and stenosis surgery in patients over 80 s

Acta Neurochirurgica (2022) 164:923–931

Degenerative spondylolisthesis (DS) is a debilitating condition that carries a high economic burden. As the global population ages, the number of patients over 80 years old demanding spinal fusion is constantly rising. Therefore, neurosurgeons often face the important decision as to whether to perform surgery or not in this age group, commonly perceived at high risk for complications.

Methods Six hundred seventy-eight elder patients, who underwent posterolateral lumbar fusion for DS (performed in three different centers) from 2012 to 2020, were screened for medical, early and late surgical complications and for the presence of potential preoperative risk factors. Patients were divided in three categories based on their age: (1) 60–69 years, (2) 70–79 years, (3) 80 and over. Multiple logistic regression was used to determine the predictive power of age and of other risk factors (i.e., ASA score; BMI; sex; presence or absence of insulin-dependent and -independent diabetes, use of anticoagulants, use of antiaggregants and osteoporosis) for the development of postoperative complications.

Results In univariate analysis, age was significantly and positively correlated with medical complications. However, when controls for other risk factors were added in the regressions, age never reached significance, with the only noticeable exception of cerebrovascular accidents. ASA score and BMI were the two risk factors that significantly correlated with the higher numbers of complication rates (especially medical).

Conclusion Patients of different age but with comparable preoperative risk factors share similar postoperative morbidity rates. When considering octogenarians for lumbar arthrodesis, the importance of biological age overrides that of chronological.

Predictors of functional recovery following surgery for foot drop due to degenerative lumbar disease

Surgery for foot drop secondary to lumbar degenerative disease is not always associated with postoperative functional improvement. It is still unclear whether early decompression results in better functional recovery and how soon surgery should be performed. This study aimed to evaluate predicting factors that affect short- and long-term recovery outcomes and to explore the relationship between timing of lumbar decompression and recovery from foot drop in an attempt to identify a cutoff time from symptom onset until decompression for optimal functional improvement.

METHODS The authors collected demographic, clinical, and radiographic data on patients who underwent surgery for foot drop due to lumbar degenerative disease. Clinical data included tibialis anterior muscle (TAM) strength before and after surgery, duration of preoperative motor weakness, and duration of radicular pain until surgery. TAM strength was recorded at the immediate postoperative period and 1 month after surgery while long-term follow-up on functional outcomes were obtained at ≥ 2 years postsurgery by telephone interview. Data including degree and duration of preoperative motor weakness as well as the occurrence of pain and its duration were collected to analyze their impact on short- and long-term outcomes.

RESULTS The majority of patients (70%) showed functional improvement within 1 month postsurgery and 40% recovered to normal or near-normal strength. Univariate analysis revealed a trend toward lower improvement rates in patients with preoperative weakness of more than 3 weeks (33%) compared with patients who were operated on earlier (76.5%, p = 0.034). In a multivariate analysis, the only significant predictor for maximal strength recovery was TAM strength before surgery (OR 6.80, 95% CI 1.38–33.42, p = 0.018). Maximal recovery by 1 month after surgery was significantly associated with sustained long-term functional improvement (p = 0.006).

CONCLUSIONS Early surgery may improve the recovery rate in patients with foot drop caused by lumbar degenerative disease, yet the strongest predictor for the extent of recovery is the severity of preoperative TAM weakness. Maximal recovery in the short-term postoperative period is associated with sustained long-term functional improvement and independence.


Lymphocele after anterior lumbar interbody fusion: a review of 1322 patients

J Neurosurg Spine 35:722–728, 2021

Anterior lumbar interbody fusion (ALIF) is an effective surgical modality for many lumbar degenerative pathologies, but a rare and infrequently reported complication is postoperative lymphocele. The goals of the present study were to review a large consecutive series of patients who underwent ALIF at a high-volume institution, estimate the rate of lymphocele occurrence after ALIF, and investigate the outcomes of patients who developed lymphocele after ALIF.

METHODS A retrospective review of the electronic medical record was completed, identifying all patients (≥ 18 years old) who underwent at a minimum a single-level ALIF from 2012 through 2019. Postoperative spinal and abdominal images, as well as radiologist reports, were reviewed for mention of lymphocele. Clinical data were collected and reported. RESULTS A total of 1322 patients underwent a minimum 1-level ALIF. Of these patients, 937 (70.9%) had either postoperative abdominal or lumbar spine images, and the resulting lymphocele incidence was 2.1% (20/937 patients). The mean ± SD age was 67 ± 10.9 years, and the male/female ratio was 1:1. Patients with lymphocele were significantly older than those without lymphocele (66.9 vs 58.9 years, p = 0.006). In addition, patients with lymphocele had a greater number of mean levels fused (2.5 vs 1.8, p < 0.001) and were more likely to have undergone ALIF at L2–4 (95.0% vs 66.4%, p = 0.007) than patients without lymphocele. On subsequent multivariate analysis, age (OR 1.07, 95% CI 1.01– 1.12, p = 0.013), BMI (OR 1.10, 95% CI 1.01–1.18, p = 0.021), and number of levels fused (OR 1.82, 95% CI 1.05–3.14, p = 0.032) were independent prognosticators of postoperative lymphocele development. Patients with symptomatic lymphocele were successfully treated with either interventional radiology (IR) drainage and/or sclerosis therapy and achieved radiographic resolution. The mean ± SD length of hospital stay was 9.1 ± 5.2 days. Ten patients (50%) were postoperatively discharged to a rehabilitation center: 8 patients (40%) were discharged to home, 1 (5%) to a skilled nursing facility, and 1 (5%) to a long-term acute care facility.

CONCLUSIONS After ALIF, 2.1% of patients were diagnosed with radiographically identified postoperative lymphocele and had risk factors such as increased age, BMI, and number of levels fused. Most patients presented within 1 month postoperatively, and their clinical presentations included abdominal pain, abdominal distension, and/or wound complications. Of note, 25% of identified lymphoceles were discovered incidentally. Patients with symptomatic lymphocele were successfully treated with either IR drainage and/or sclerosis therapy and achieved radiographic resolution.

Brain infarctions after glioma surgery

Acta Neurochirurgica (2021) 163:3097–3108

Prevalence, radiological characteristics, and risk factors for peritumoral infarctions after glioma surgery are not much studied. In this study, we assessed shape, volume, and prevalence of peritumoral infarctions and investigated pos- sible associated factors.

Methods In a prospective single-center cohort study, we included all adult patients operated for diffuse gliomas from January 2007 to December 2018. Postoperative infarctions were segmented using early postoperative MRI images, and volume, shape, and location of postoperative infarctions were assessed. Heatmaps of the distribution of tumors and infarctions were created.

Results MRIs from 238 (44%) of 539 operations showed restricted diffusion in relation to the operation cavity, interpreted as postoperative infarctions. Of these, 86 (36%) were rim-shaped, 103 (43%) were sector-shaped, 40 (17%) were a combination of rim- and sector-shaped, and six (3%) were remote infarctions. Median infarction volume was 1.7 cm3 (IQR 0.7–4.3, range 0.1–67.1). Infarctions were more common if the tumor was in the temporal lobe, and the map shows more infarctions in the periventricular watershed areas. Sector-shaped infarctions were more often seen in patients with known cerebrovascular dis- ease (47.6% vs. 25.5%, p = 0.024). There was a positive correlation between infarction volume and tumor volume (r = 0.267, p < 0.001) and infarction volume and perioperative bleeding (r = 0.176, p = 0.014). Moreover, there was a significant positive association between age and larger infarction volumes (r = 0.193, p = 0.003). Infarction rates and infarction volumes varied across individual surgeons, p = 0.037 (range 32–72%) and p = 0.026.

Conclusions In the present study, peritumoral infarctions occurred in 44% after diffuse glioma operations. Infarctions were more common in patients operated for tumors in the temporal lobe but were not more common following recurrent surgeries. Sector-shaped infarctions were more common in patients with known cerebrovascular disease. Increasing age, larger tumors, and more perioperative bleeding were factors associated with infarction volumes. The risk of infarctions and infarction volumes may also be surgeon-dependent.

Perioperative complications of deep brain stimulation among patients with advanced age

J Neurosurg 135:1421–1428, 2021

Deep brain stimulation (DBS) is an elective procedure that can dramatically enhance quality of life. Because DBS is not considered lifesaving, it is important that providers produce consistently good outcomes, and one factor they usually consider is patient age. While older age may be a relative contraindication for some elective surgeries, the progressive nature of movement disorders treated with DBS may suggest that older patients stand to benefit substantially from surgery. To better understand the risks of treating patients of advanced age with DBS, this study compares perioperative complication rates in patients ≥ 75 to those < 75 years old.

METHODS Patients undergoing DBS surgery for various indications by a single surgeon (May 2013–July 2019) were stratified into elderly (age ≥ 75 years) and younger (age < 75 years) cohorts. The risks of common perioperative complications and various outcome measures were compared between the two age groups using risk ratios (RRs) and 95% confidence intervals (CIs).

RESULTS A total of 861 patients were available for analysis: 179 (21%) were ≥ 75 years old and 682 (79%) were < 75 years old (p < 0.001). Patients ≥ 75 years old, compared with those < 75 years old, did not have significantly different RRs (95% CIs) of seizure (RR 0.4, 95% CI 0.1–3.3), cerebrovascular accident (RR 1.9, 95% CI 0.4–10.3), readmission within 90 days of discharge (RR 1.22, 95% CI 0.8–1.8), explantation due to infection (RR 2.5, 95% CI 0.4–15.1), or surgical revision (for lead, RR 2.5, 95% CI 0.4–15.1; for internal pulse generator, RR 3.8, 95% CI 0.2–61.7). Although the risk of postoperative intracranial bleeding was higher in the elderly group (6.1%) than in the younger group (3.1%), this difference was not statistically significant (p = 0.06). However, patients ≥ 75 years old did have significantly increased risk of altered mental status (RR 2.5, 95% CI 1.6–4.0), experiencing more than a 1-night stay (RR 1.7, 95% CI 1.4–2.0), and urinary retention (RR 2.3, 95% CI 1.2–4.2; p = 0.009).

CONCLUSIONS Although elderly patients had higher risks of certain outcome measures than younger patients, this study showed that elderly patients undergoing DBS for movement disorders did not have an increased risk of more serious complications, such as intracranial hemorrhage, infection, or readmission. Advanced age alone should not be considered a contraindication for DBS.

Risk factors for polyetheretherketone cage subsidence following minimally invasive transforaminal lumbar interbody fusion

Acta Neurochirurgica (2021) 163:2557–2565

Interbody cage subsidence is a postoperative complication leading to poor outcomes after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). This study aimed to identify risk factors of cage subsidence in lumbar spinal diseases after MIS-TLIF using polyetheretherketone (PEEK) cage.

Methods In this retrospective cohort study, plain radiographs and three-dimensional computed tomography (3D-CT) performed 12 months after MIS-TLIF were evaluated, and the risk of cage subsidence was calculated with odds ratio (OR), confidence interval (CI), and logistic regression analysis.

Results A total of 114 patients (mean age, 65 years) and 135 levels were included in this study: 80 (59.3%) with and 55 (40.7%) without cage subsidence. Multifidus atrophy showed the strongest association with PEEK cage subsidence (p < 0.001). Compared to those with normal mass, the odds of PEEK cage subsidence were 76.0 (95% CI: 3.9–1472.9) for severe atrophy. The factors significantly associated with cage subsistence were posterior cage position (OR = 4.2; p = 0.005), cage height ≥ 12 mm (OR = 7.6; p = 0.008), use of an autograft mixed with demineralized bone matrix (DBM) (OR = 5.8; p = 0.002), body mass index (BMI) > 27.5 kg/m2 (OR = 4.2; p = 0.03), and titanium-coated PEEK (Ti-PEEK) cage-type (OR = 38.4, p = 0.02).

Conclusions In MIS-TLIF with a PEEK cage, the factors associated with an increased risk of cage subsidence were higher BMI, increased severity of multifidus muscle atrophy, Ti-coated PEEK cage-type, cage height ≥ 12 mm, use of DBM mixed autograft, and posterior cage position.

Hemorrhage Following Complete Arteriovenous Malformation ResectionWith No Detectable Recurrence

Neurosurgery 89:212–219, 2021

Although recurrence and de novo formation of arteriovenous malformations (AVMs) have been reported following complete resection, the occurrence of hemorrhage in the same location of an AVM with no detectable lesion (lesion-negative hemorrhage) has not been described after microsurgery.

OBJECTIVE: To characterize the incidence and properties of lesion-negative hemorrhage following complete microsurgical resection

METHODS: A prospectively maintained registry of AVM patients seen at our institution between 1990 and 2017 was used. Microsurgically treated patients were selected, and the incidence of a lesion-negative hemorrhage was calculated and described with a Kaplan- Meier curve. Baseline characteristics as well as functional outcome at last follow-up were compared between patients with and without a lesion-negative hemorrhage.

RESULTS: From a total of 789 AVM patients, 619 (79%) were treated, and 210 out of 619 patients (34%) underwent microsurgery with or without preoperative embolization or radiosurgery. The microsurgically treated cohort was followed up for a mean of 6.1 ± 3.0 yr after surgery with 5 (2.4%) patients experiencing postresection lesion-negative hemorrhage (3.9 per 1000 person-years) at an average of 8.6 ± 9.0 yr following surgery. Follow-up angiograms after hemorrhage (up to 2 mo posthemorrhage) confirmed the absence of a recurrent or de novo AVM in all cases. All patients with a lesion-negative hemorrhage initially presented with rupture before resection (Fisher P = .066; log-rank P = .057). The occurrence of a lesion-negative hemorrhage was significantly associated with worse modified Rankin scale scores at last follow-up (P = .031).

CONCLUSION: A lesion-negative hemorrhage can occur following complete microsurgical resection in up to 2.4% of patients. Exploration of possible underlying causes is warranted.

Retrograde ejaculation following anterior lumbar surgery: a systematic review and pooled analysis

J Neurosurg Spine July 16, 2021

The present systematic review and pooled analysis aims to assess the incidence and risk factors for the development of retrograde ejaculation (RE) following first-time open anterior lumbar surgery.

METHODS A systematic MEDLINE review via PubMed was performed, identifying 130 clinical papers relating to the topic. Eighteen publications were selected according to predetermined inclusion and exclusion criteria and were used to determine the incidence of RE. Only the publications that provided data on surgical risk factors present specifically in the men in the study were included in the analysis of risk factors.

RESULTS Of the 2503 men included, there were 57 reported events of RE (2.3%). Of the cases for which long-term data were provided, 45.8% had resolved by final follow-up. There was a statistically significant increased risk associated with a transperitoneal as opposed to a retroperitoneal approach (8.6% vs 3.2%), as well as with the use of recombinant human bone morphogenetic protein–2 (rhBMP-2) in anterior lumbar interbody fusion (ALIF) as opposed to ALIF with bone graft or arthroplasty in controls (5.0% vs 1.8%). However, when excluding from analysis the patients operated on prior to the FDA’s 2008 warning that commented on the drug’s neuroinflammatory properties, there was no significant difference in rates of RE in patients receiving rhBMP-2 versus the control group (2.4% vs 2.5%). There was no significant difference in risk based on single- versus multilevel procedure or on ALIF versus arthroplasty.

CONCLUSIONS In a pooled analysis of currently published data on men undergoing first-time open anterior lumbar surgery, this study found an overall incidence of RE of 2.3%. Nearly half of these patients recovered, reporting resolution of symptoms anywhere between 3 months and 48 months. Analysis of risk factors was limited by a paucity of published literature segregating data by sex. However, there was an increased risk associated with rhBMP-2 only when including data collected prior to the FDA warning on its detrimental properties. The authors therefore posit that the risk of RE is probably overestimated in the literature, given that the vast majority of the data available were collected prior to this warning and given the subsequent implementation of precautions when handling rhBMP-2.


Perioperative and swallowing outcomes in patients undergoing 4- and 5-level anterior cervical discectomy and fusion

J Neurosurg Spine 34:849–856, 2021

Anterior cervical discectomy and fusion (ACDF) is a common and robust procedure performed on the cervical spine. Literature on ACDF for 4 or more segments is sparse. Increasing the number of operative levels increases surgical complexity, tissue retraction, and risks of complications, particularly dysphagia. The overall risks of these complications and rates of dysphagia are not well studied for surgery on 4 or more segments. In this study, the authors evaluated their institution’s perioperative experience with 4- and 5-level ACDFs.

METHODS The authors retrospectively reviewed patients who underwent 4- or 5-level ACDF at their institution over a 6-year period (May 2013–May 2019). Patient demographics, perioperative complications, readmission rates, and swallowing outcomes were recorded. Outcomes were analyzed with a multivariate linear regression.

RESULTS A total of 174 patients were included (167 had 4-level and 7 had 5-level ACDFs). The average age was 60.6 years, and 54.0% of patients (n = 94) were men. A corpectomy was performed in 12.6% of patients (n = 22). After surgery, 56.9% of patients (n = 99) experienced dysphagia. The percentage of patients with dysphagia decreased to 22.8% (37/162) at 30 days, 12.9% (17/132) at 90 days, and 6.3% (5/79) and 2.8% (1/36) at 1 and 2 years, respectively. Dysphagia was more likely at 90 days postoperatively in patients with gastroesophageal reflux (OR 4.4 [95% CI 1.5–12.8], p = 0.008), and the mean (± SD) lordosis change was greater in patients with dysphagia than those without at 90 days (19.8° ± 13.3° vs 9.1° ± 10.2°, p = 0.003). Dysphagia occurrence did not differ with operative implants, including graft and interbody type. The mean length of time to solid food intake was 2.4 ± 2.1 days. Patients treated with dexamethasone were more likely to achieve solid food intake prior to discharge (OR 4.0 [95% CI 1.5–10.6], p = 0.004). Postsurgery, 5.2% of patients (n = 9) required a feeding tube due to severe approach-related dysphagia. Other perioperative complication rates were uniformly low. Overall, 8.6% of patients (n = 15) returned to the emergency department within 30 days and 2.9% (n = 5) required readmission, whereas 1.1% (n = 2) required unplanned return to surgery within 30 days.

CONCLUSIONS This is the largest series of patients undergoing 4- and 5-level ACDFs reported to date. This procedure was performed safely with minimal intraoperative complications. More than half of the patients experienced in-hospital dysphagia, which increased their overall length of stay, but dysphagia decreased over time.

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