Category: complications

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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.

 

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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.

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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.

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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.

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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.

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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.

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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.

 

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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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Low-Dose Intravenous Heparin Infusion After Aneurysmal Subarachnoid Hemorrhage is Associated With Decreased Risk of Delayed Neurological Deficit and Cerebral Infarction

Neurosurgery 88 (3)2021: 523–530

Patients who survive aneurysmal subarachnoid hemorrhage (aSAH) are at risk for delayed neurological deficits (DND) and cerebral infarction. In this exploratory cohort comparison analysis, we compared in-hospital outcomes of aSAH patients administered a low-dose intravenous heparin (LDIVH) infusion (12 U/kg/h) vs those administered standard subcutaneous heparin (SQH) prophylaxis for deep vein thrombosis (DVT; 5000 U, 3 × daily).

OBJECTIVE: To assess the safety and efficacy of LDIVH in aSAH patients.

METHODS: We retrospectively analyzed 556 consecutive cases of aSAH patients whose aneurysm was secured by clipping or coiling at a single institution over a 10-yr period, including 233 administered the LDIVH protocol and 323 administered the SQH protocol. Radiological and outcome datawere compared between the 2 cohorts using multivariable logistic regression and propensity score-based inverse probability of treatment weighting (IPTW).

RESULTS: The unadjusted rate of cerebral infarction in the LDIVH cohort was half that in SQH cohort (9 vs 18%; P = .004). Multivariable logistic regression showed that patients in the LDIVH cohort were significantly less likely than those in the SQH cohort to have DND (odds ratio (OR) 0.53 [95% CI: 0.33, 0.85]) or cerebral infarction (OR 0.40 [95% CI: 0.23, 0.71]). Analysis following IPTWshowed similar results. Rates of hemorrhagic complications, heparin-induced thrombocytopenia and DVT were not different between cohorts.

CONCLUSION: This cohort comparison analysis suggests that LDIVH infusion may favorably influence the outcome of patients after aSAH. Prospective studies are required to further assess the benefit of LDIVH infusion in patients with aSAH.

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Vitamin D—A New Perspective in Treatment of Cerebral Vasospasm

Neurosurgery 88 (3) 2021: 674–685

Cerebral vasospasm (CVS) is a frequent complication after subarachnoid hemorrhage (SAH), with no sufficient therapy and a complex pathophysiology.

OBJECTIVE: To explore the vitamin D system as a potential treatment for CVS.

METHODS: 25-vitamin D3 levels tested between 2007 and 2015 and data of SAH patients admitted during themonthswith a peak vs nadir of VitD3 valueswere analyzed, retrospectively. We prospectively correlated VitD3 and vasospasm/outcome data in SAH patients admitted in 2017. An experimental mice SAH model and cell culture model were used to investigate the effect of 1,25-dihydroxyvitamin D3 (1,25-VitD3). Additionally, the mediators acting in the VitD mechanism were researched and detected.

RESULTS: Based on the retrospective analysis demonstrating an increased frequency of vasospasm in SAH patients during the low vitamin D period in winter, we started basic research experiments. Active 1,25-VitD3 hormone attenuated CVS, neurological deficit, and inflammation after intrathecal blood injection inmice. Deletion of the vitaminDreceptor in the endothelium or in myeloid cells decreased the protective 1,25-VitD3 effect. Co-culture experiments ofmyeloid and endothelial cells with blood confirmed the anti-inflammatory 1,25-VitD3 effect but also revealed an induction of stroma-cell-derived factor 1α (SDF1α), vascular endothelial growth factor, and endothelial nitric oxide synthase by 1,25-VitD3. In mice, SDF1α mimicked the protective effect of 1,25-VitD3 against CVS. From bench to bedside, CVS severity was inversely correlated with vitamin D plasma level, prospectively. Patients with more severe CVS exhibited attenuated expression of SDF1α and 1,25-VitD3- responsive genes on circulating myeloid cells.

CONCLUSION: 1,25-VitD3 attenuates CVS after SAH by inducing SDF1α. However, VitD administration should be tested as optional treatment to prevent CVS.

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Cranioplasty following ventriculoperitoneal shunting: lessons learned

Acta Neurochirurgica (2021) 163:441–446

Cranioplasty (CP) is considered as a straightforward and technically unchallenging operation; however, complication rates are high reaching up to 56%. Presence of a ventriculoperitoneal shunt (VPS) and timing of CP are reported risk factors for complications. Pressure gradients and scarring at the site of the cranial defect seem to be critical in this context. The authors present their experiences and lessons learned.

Methods A consecutive series of all patients who underwent CP at the authors’ institution between 2002 and 2017 were included in this retrospective analysis. Complications were defined as all events that required reoperation. Logistic regression analysis and chi-squared test were conducted to evaluate the complication rates according to suspected risk factors.

Results A total of 302 patients underwent cranioplasty between 2002 and 2017. The overall complication rate was 17.5%. Complications included epi-/subdural fluid collection (7.3%) including hemorrhage (4.6%) and hygroma (2.6%), bone graft resorption (5.3%), bone graft infection (2.0%), and hydrocephalus (5.7%). Overall, 57 patients (18.9%) had undergone shunt implantation prior to CP. The incidence of epi-/subdural fluid collection was 19.3% in patients with VPS and 4.5% in patients without VPS, OR 5.1 (95% CI 2.1–12.4). Incidence of hygroma was higher in patients who underwent early CP. Patients with temporary shunt ligation for CP did not suffer from complications.

Conclusion CP in patients with a VPS remains a high-risk procedure. Any effort to understand the pressure dynamics and to reduce factors that may trigger the formation of a large epidural space must be undertaken.

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Prepontine Shunting for Pseudotumor Cerebri in Previously Failed Shunt Patients

Neurosurgery 88(2)2021: 306–312

Shunting procedures have a high failure rate when used to treat pseudotumor cerebri (PTC) patients who have failed medical therapy. This failure is believed to be attributable to the collapsibility of the ventricular systemwhenexposed to increased differential pressure gradients in the cerebral spinal fluid compartments caused by ventriculoperitoneal shunts (VPS).

OBJECTIVE: To investigate whether prepontine/interpeduncular cistern shunting may be a reasonable alternative to VPS intervention in PTC patients with history of shunt failure. There have been no large series of cisternal-peritoneal shunt (CPS) patients in the PTC population.

METHODS: A retrospective review of 49 patients with placement of CPS for PTC with 2 failed prior shunting procedures was performed. Shunt survivability was based on shunt patency and resolution of ophthalmologic symptoms and cranial nerve deficits. All patientswere followed for aminimum of 3 yrwith serial ophthalmologic and neurosurgical evaluations.

RESULTS: At 3 yr, 44 of the 49 (88.9%) patients had working CPS. Three patients in this group had infections requiring complete shunt removal. Excluding infections, 44 of 46 (95.5%) shunts were functional at 3 yr. There were 3 small, asymptomatic hemorrhages that did not increase patient length of stay, and there were no catastrophic hemorrhages or strokes. There were also no abdominal complications related to shunt placement.

CONCLUSION: CPS is a viable alternative to VPS in PTC patients who have failed traditional shunting methods to give these patients a persistent benefit of a working shunt. The procedure provides this solution with low operative and perioperative morbidity.

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Revision and complication rates in adult shunt surgery

Acta Neurochirurgica (2021) 163:447–454

CSF diversion with shunt placement is frequently associated with need for later revisions as well as surgical complications. We sought to review revision and complication rates following ventriculoperitoneal, ventriculoatrial and cystoperitoneal shunt placement in adult patients, and to identify potential risk factors for revision surgery and postoperative complications.

Method Included patients were adults (≥ 18 years) who underwent primary shunt insertion at St. Olavs Hospital in Trondheim, Norway, from 2008 through 2017. The electronic medical records and diagnostic imaging from all hospitals in our catchment area were retrospectively reviewed. Follow-up ranged from 1 to 11 years. Complications were graded according to the Landriel Ibañez classification system.

Results Of the 227 patients included, 47 patients (20.7%) required revision surgery during the follow-up. In total, 90 revision surgeries were performed during follow-up. The most common cause for the first revision was infection (5.7%) and for all revisions proximal occlusion (30.0%). A total of 103 patients (45.4%) experienced ≥ 1 complication(s). Mild to moderate complications (grade I and II) were detected in 35.0% of all procedures. Severe or fatal complications (grade III and IV) were observed in 8.2% of all procedures. Urinary tract infections and pneumonia were common postoperatively (13.9% and 7.3%, respectively), and the most common IIb complication was shunt misplacement (proximally or distally). Two out of fourteen deaths within 30 days were directly associated with surgery. We did not find that aetiology/indication, age or gender influenced the occurrence of revision surgery or a grade III or IV complication.

Conclusions Shunt surgery continues to be a challenge both in terms of revision rates and procedure-related complications. However, the prediction of patients at risk remains difficult. A multidimensional focus is probably needed to reduce risks.

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Risk factors for developing subdural hematoma: a registry-based study in 1457 patients with shunted idiopathic normal pressure hydrocephalus

J Neurosurg 134:668–677, 2021

Subdural hematomas and hygromas (SDHs) are common complications in idiopathic normal pressure hydrocephalus (iNPH) patients with shunts. In this registry-based study, patients with shunted iNPH were screened nationwide to identify perioperative variables that may increase the risk of SDH.

METHODS The Swedish Hydrocephalus Quality Registry was reviewed for iNPH patients who had undergone shunt surgery in Sweden in 2004–2014. Potential risk factors for SDH were recorded preoperatively and 3 months after surgery. Drug prescriptions were identified from a national pharmacy database. Patients who developed SDHs were compared with those without SDHs.

RESULTS The study population consisted of 1457 patients, 152 (10.4%) of whom developed an SDH. Men developed an SDH more often than women (OR 2.084, 95% CI 1.421–3.058, p < 0.001). Patients on platelet aggregation inhibitors developed an SDH more often than those who were not (OR 1.733, 95% CI 1.236–2.431, p = 0.001). At surgery, shunt opening pressures had been set 5.9 mm H2O lower in the SDH group than in the no-SDH group (109.6 ± 24.1 vs 115.5 ± 25.4 mm H2O, respectively, p = 0.009). Antisiphoning devices (ASDs) were used in 892 patients but did not prevent SDH. Mean opening pressures at surgery and the follow-up were lower with shunts with an ASD, without causing more SDHs. No other differences were seen between the groups.

CONCLUSIONS iNPH patients in this study were diagnosed and operated on in routine practice; thus, the results represent everyday care. Male sex, antiplatelet medication, and a lower opening pressure at surgery were risk factors for SDH. Physical status and comorbidity were not. ASD did not prevent SDH, but a shunt with an ASD allowed a lower opening pressure without causing more SDHs.

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Neurological events due to pedicle screw malpositioning with lateral fluoroscopy–guided pedicle screw insertion

J Neurosurg Spine 33:806–811, 2020

The risk of novel postoperative neurological events due to pedicle screw malpositioning in lumbar fusion surgery is minimized by using one of the several image-guided techniques for pedicle screw insertion. These techniques for guided screw insertion range from intraoperative fluoroscopy to intraoperative navigation. A practical technique consists of anatomical identification of the screw entry point followed by lateral fluoroscopy used for guidance during insertion of the screw. This technique is available in most clinics and is less expensive than intraoperative navigation. However, the safety of lateral fluoroscopy–guided pedicle screw placement with regard to novel postoperative neurological events due to screw malposition has been addressed only rarely in the literature. In this study the authors aimed to determine the rate of novel postoperative neurological events due to intraoperative and postoperatively established screw malpositioning during lateral fluoroscopy–assisted screw insertion.

METHODS Included patients underwent lateral fluoroscopy–assisted lumbosacral screw insertion between January 2012 and August 2017. The occurrence of novel postoperative neurological events was analyzed from patient files. In case of an event, surgical reports were screened for the occurrence of intraoperative screw malposition. Furthermore, postoperative CT scans were analyzed to identify and describe possible screw malposition.

RESULTS In total, 246 patients with 1079 screws were included. Novel postoperative neurological events were present in 36 patients (14.6%). In 8 of these 36 patients (3.25% of the total study population), the neurological events could be directly attributed to screw malposition. Screw malpositioning was caused either by problematic screw insertion with immediate screw correction (4 patients) or by malpositioned screws for which the malposition was established postoperatively using CT scans (4 patients). Three patients with screw malposition underwent revision surgery without subsequent symptom relief.

CONCLUSIONS Lateral fluoroscopy–assisted lumbosacral screw placement results in low rates of novel postoperative neurological events caused by screw malposition. In the majority of patients suffering from novel postoperative neurological events, these events could not be attributed to screw malpositioning, but rather were due to postoperative neurapraxia of peripheral nerves, neuropathy, or intraoperative traction of nerve roots.

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Nasopharyngeal muscle patch for the management of internal carotid artery injury in endoscopic endonasal surgery

J Neurosurg 133:1382–1387, 2020

Injury to the internal carotid artery (ICA) is the most critical complication of endoscopic endonasal skull base surgery. Packing with a crushed muscle graft at the injury site has been an effective management technique to control bleeding without ICA sacrifice. Obtaining the muscle graft has typically required access to another surgical site, however. To address this concern, the authors investigated the application of an endonasally harvested longus capitis muscle patch for the management of ICA injury.

METHODS One colored silicone-injected anatomical specimen was dissected to replicate the surgical access to the nasopharynx and the stepwise dissection of the longus capitis muscle in the nasopharynx. Two representative cases were selected to illustrate the application of the longus capitis muscle patch and the relevance of clinical considerations.

RESULTS A suitable muscle graft from the longus capitis muscle could be easily and quickly harvested during endoscopic endonasal skull base surgery. In the illustrative cases, the longus capitis muscle patch was successfully used for secondary prevention of pseudoaneurysm formation following primary bleeding control on the site of ICA injury.

CONCLUSIONS Nasopharyngeal harvest of a longus capitis muscle graft is a safe and practical method to manage ICA injury during endoscopic endonasal surgery.

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Diabetes Insipidus After Endoscopic Transsphenoidal Surgery

Neurosurgery 2020 DOI:10.1093/neuros/nyaa148

Diabetes insipidus (DI) is a recognized transient or permanent complication following transsphenoidal surgery (TSS) for pituitary tumors.

OBJECTIVE: To describe significant experience with the incidence of DI after TSS, identifying predictive characteristics and describing our diagnosis and management of postoperative DI.

METHODS: A retrospective analysis was performed of 700 patients who underwent endoscopic TSS for resection of pituitary adenoma (PA), Rathke cleft cyst (RCC), or craniopharyngioma. Inclusion criteria included at least 1 wk of follow-up for diagnosis of postoperative DI. Permanent DI was defined as DI symptoms and/or need for desmopressinmore than 1 yr postoperatively. All patients with at least 1 yr of follow-up (n=345) were included in analyses of permanent DI. Multivariable logistic regression models were constructed to identify predictors of transient or permanent postoperative DI.

RESULTS: The overall rate of any postoperative DI was 14.7% (103/700). Permanent DI developed in 4.6% (16/345). The median follow-up was 10.7mo (range: 0.2-136.6). Compared to patients with PA, patients with RCC (odds ratio [OR] = 2.2, 95% CI: 1.2-3.9; P = .009) and craniopharyngioma (OR = 7.0, 95% CI: 2.9-16.9; P ≤ .001) were more likely to develop postoperative DI. Furthermore, patients with RCC (OR = 6.1, 95% CI: 1.8-20.6; P = .004) or craniopharyngioma (OR = 18.8, 95% CI: 4.9-72.6; P ≤ .001) were more likely to develop permanent DI compared to those with PA.

CONCLUSION: Although transient DI is a relatively common complication of endoscopic and microscopic TSS, permanent DI is much less frequent. The underlying pathology is an important predictor of both occurrence and permanency of postoperative DI.

 

 

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Lower Hounsfield units on CT are associated with cage subsidence after anterior cervical discectomy and fusion

J Neurosurg Spine 33:425–432, 2020

A consequence of anterior cervical discectomy and fusion (ACDF) is graft subsidence, potentially leading to kyphosis, nonunion, foraminal stenosis, and recurrent pain. Bone density, as measured in Hounsfield units (HUs) on CT, may be associated with subsidence. The authors evaluated the association between HUs and subsidence rates after ACDF.

METHODS A retrospective study of patients treated with single-level ACDF at the University of California, San Francisco, from 2008 to 2017 was performed. HU values were measured according to previously published methods. Only patients with preoperative CT, minimum 1-year follow-up, and single-level ACDF were included. Patients with posterior surgery, tumor, infection, trauma, deformity, or osteoporosis treatment were excluded. Changes in segmental height were measured at 1-year follow-up compared with immediate postoperative radiographs. Subsidence was defined as segmental height loss of more than 2 mm.

RESULTS A total of 91 patients met inclusion criteria. There was no significant difference in age or sex between the subsidence and nonsubsidence groups. Mean HU values in the subsidence group (320.8 ± 23.9, n = 8) were significantly lower than those of the nonsubsidence group (389.1 ± 53.7, n = 83, p < 0.01, t-test). There was a negative correlation between the HU values and segmental height loss (Pearson’s coefficient −0.735, p = 0.01). Using receiver operating characteristic curves, the area under the curve was 0.89, and the most appropriate threshold of HU value was 343.7 (sensitivity 77.1%, specificity 87.5%). A preoperative lower HU is a risk factor for postoperative subsidence (binary logistic regression, p < 0.05). The subsidence rate and distance between allograft and polyetheretherketone (PEEK) materials were not significantly different (PEEK 0.9 ± 0.7 mm, allograft 1.0 ± 0.7 mm; p > 0.05).

CONCLUSIONS Lower preoperative CT HU values are associated with cage subsidence in single-level ACDF. Preoperative measurement of HUs may be useful in predicting outcomes after ACDF.

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Predictors of Complications, Functional Outcome, and Morbidity in a Large Cohort TreatedWith Flow Diversion

Neurosurgery DOI:10.1093/neuros/nyz508

A dramatic improvement in obliteration rates of large, wide-necked aneurysms has been observed after the FDA approved the Pipeline Embolization Device (PED) in 2011.

OBJECTIVE: To assess the predictors of complications, morbidity, and unfavorable outcomes in a large cohort of patients with aneurysms treated with PED.

METHODS: A retrospective chart review of a prospectively maintained database for subjects treated with flow diversion from 2010 to 2019.

RESULTS: A total of 598 aneurysms were treated during a period extending from 2010 to 2019 (84.28% females, mean age 55.5 yr, average aneurysm size 8.49 mm). Morbidity occurred at a rate of 5.8% and mortality at a rate of 2.2%. Ischemic stroke occurred at a rate of 3%, delayed aneurysmal rupture (DAR) at 1.2%, and distal intraparenchymal hemorrhage (DIPH) at 1.5%. On multivariate analysis, the predictor of stroke was aneurysm size>15 mm. Predictors of DAR were previous subarachnoid hemorrhage (SAH), increasing aneurysm size, and posterior circulation aneurysm. Predictors of DIPH were using more than 1 PED and baseline P2Y12 value. Predictors of in-stent stenosis were the increasing year of treatment and balloon angioplasty, whereas increasing age and previous treatment were negatively associated with in-stent stenosis. Predictors of morbidity were posterior circulation aneurysms, increasing aneurysm size, and hypertension, and incidental aneurysm diagnosis was protective for morbidity.

CONCLUSION: Flow diversion is a safe and effective treatment option for aneurysms. A better understanding of predictive factors of complications, morbidity, and functional outcomes is of high importance for a more accurate risk assessment.

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PEEK versus titanium cages in lateral lumbar interbody fusion: a comparative analysis of subsidence

Neurosurg Focus 49 (3):E10, 2020

The authors have provided a review of radiographic subsidence after lateral lumbar interbody fusion (LLIF) as a comparative analysis between titanium and polyetheretherketone (PEEK) cages. Many authors describe a reluctance to use titanium cages in spinal fusion secondary to subsidence concerns due to the increased modulus of elasticity of metal cages. The authors intend for this report to provide observational data regarding the juxtaposition of these two materials in the LLIF domain.

METHODS A retrospective review of a prospectively maintained database identified 113 consecutive patients undergoing lateral fusion for degenerative indications from January to December 2017. The surgeons performing the cage implantations were two orthopedic spine surgeons and two neurosurgeons. Plain standing radiographs were obtained at 1–2 weeks, 8–12 weeks, and 12 months postoperatively. Using a validated grading system, interbody subsidence into the endplates was graded at these time points on a scale of 0 to III. The primary outcome measure was subsidence between the two groups. Secondary outcomes were analyzed as well.

RESULTS Of the 113 patients in the sample, groups receiving PEEK and titanium implants were closely matched at 57 and 56 patients, respectively. Cumulatively, 156 cages were inserted and recombinant human bone morphogenetic protein– 2 (rhBMP-2) was used in 38.1%. The average patient age was 60.4 years and average follow-up was 75.1 weeks. Subsidence in the titanium group in this study was less common than in the PEEK cage group. At early follow-up, groups had similar subsidence outcomes. Statistical significance was reached at the 8- to 12-week and 52-week follow-ups, demonstrating more subsidence in the PEEK cage group than the titanium cage group. rhBMP-2 usage was also highly correlated with higher subsidence rates at all 3 follow-up time points. Age was correlated with higher subsidence rates in univariate and multivariate analysis.

CONCLUSIONS Titanium cages were associated with lower subsidence rates than PEEK cages in this investigation. Usage of rhBMP-2 was also robustly associated with higher endplate subsidence. Each additional year of age correlated with an increased subsidence risk. Subsidence in LLIF is likely a response to a myriad of factors that include but are certainly not limited to cage material. Hence, the avoidance of titanium interbody implants secondary solely to concerns over a modulus of elasticity likely overlooks other variables of equal or greater importance.

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