Two cases of SMA syndrome after neurosurgical injury to the frontal aslant tract

Acta Neurochirurgica (2023) 165:2473–2478

Supplementarymotor area (SMA) syndrome is characterised by transient disturbance in volitional movement and speech production which classically occurs after injury to the medial premotor area.

We present two cases of SMA syndrome following isolated surgical injury to the frontal aslant tract (FAT) with the SMA intact. The first case occurred after resection of a left frontal operculum tumour. The second case occurred after a transcortical approach to a ventricular neurocytoma. The clinical picture and fMRI activation patterns during recovery were typical for SMA syndrome and support the theory that the FAT is a critical bundle in the SMA complex function.

 

The Role of Prolonged Bed Rest in Postoperative Cerebrospinal Fluid Leakage After Surgery of Intradural Pathology

Neurosurgery 93:563–575, 2023

Postoperative cerebrospinal fluid leakage (CSFL) is a feared complication after surgery on intradural pathologies and may cause postoperative complications and subsequently higher treatment costs.

OBJECTIVE: To assess whether prolonged bed rest may lower the risk of CSFL.

METHODS: We performed a retrospective cohort study including patients with intradural pathologies who underwent surgery at our department between 2013 and 2021. Cohorts included patients who completed 3 days of postoperative bed rest and patients who were mobilized earlier. The primary end point was the occurrence of clinically proven CSFL.

RESULTS: Four hundred and thirty-three patients were included (female [51.7%], male [48.3%]) with a mean age of 48 years (SD ±20). Bed rest was ordered in 315 cases (72.7%). In 7 cases (N = 7/433, 1.6%), we identified a postoperative CSFL. Four of them (N = 4/118) did not preserve bed rest, showing no significant difference to the bed rest cohort (N = 3/315; P = .091). In univariate analysis, laminectomy (N = 4/61; odds ratio [OR] 8.632, 95% CI 1.883-39.573), expansion duraplasty (N = 6/70; OR 33.938, 95% CI 4.019-286.615), and recurrent surgery (N = 5/66; OR 14.959, 95% CI 2.838-78.838) were significant risk factors for developing CSFL. In multivariate analysis, expansion duraplasty was confirmed as independent risk factor (OR 33.937, 95% CI 4.018-286.615, P = .001). In addition, patients with CSFL had significan’t higher risk for meningitis (N = 3/7; 42.8%, P = .001).

CONCLUSION: Prolonged bed rest did not protect patients from developing CSFL after surgery on intradural pathologies. Avoiding laminectomy, large voids, and minimal invasive approaches may play a role in preventing CSFL. Furthermore, special caution is indicated if expansion duraplasty was done.

 

Bilateral Low-Frequency Hearing Impairment After Microvascular Decompression Surgery

Neurosurgery 93:662–669, 2023

Hearing impairment is an important complication of microvascular decompression (MVD). In patients after MVD, we have occasionally noted slight to moderate hearing deterioration at low frequencies that is difficult to detect using pure tone average.

OBJECTIVE: To assess the incidence and features of low-frequency hearing impairment (LF-HI) after MVD and evaluate its associated factors.

METHODS: This single-center, retrospective observational study assessed the audiometric outcome of 270 patients who underwent MVD between January 2015 and December 2020. Preoperative and postoperative hearing levels were compared for each frequency. LF-HI was defined as a hearing deterioration of ≥15 dB at 125, 250, or 500 Hz. The incidence, symptoms, and associated factors of LF-HI were analyzed.

RESULTS: Statistical analysis of the patients overall demonstrated slight but significant decreases in the hearing level after MVD at lower frequencies on both the operative and contralateral sides. Eighty-one patients (30.0%) had LF-HI: 49 on the operative side, 24 on the contralateral side, and 8 on both sides, while pure tone average was worsened in 5 patients (1.8%). Subjective symptoms, including hearing deterioration, ear fullness, tinnitus, and dizziness, developed in 10.4% of the patients with LF-HI but improved subsequently within several weeks. “Older age” and “operative side” were associated with LF-HI.

CONCLUSION: Decreases in lower-frequency hearing levels in both the ipsilateral and contralateral (nonoperative) ears were observed after trigeminal neuralgia and hemifacial spasm surgery. LF-HI does not cause permanent symptoms but may be a noteworthy phenomenon, possibly involved in the contralateral hearing loss encountered occasionally after other types of posterior cranial fossa surgery.

Postoperative Spinal Cerebrospinal Fluid-Venous Fistulas Associated With Dural Tears in Patients With Intracranial Hypotension or Superficial Siderosis

Neurosurgery 93:473–479, 2023

Postoperative spinal cerebrospinal fluid (CSF) leaks are common but rarely cause extensive CSF collections that require specialized imaging to detect the site of the dural breach.

OBJECTIVE: To investigate the use of digital subtraction myelography (DSM) for patients with extensive extradural CSF collections after spine surgery.

METHODS: A retrospective review was performed to identify a consecutive group of patients with extensive postoperative spinal CSF leaks who underwent DSM.

RESULTS: Twenty-one patients (9 men and 12 women) were identified. The mean age was 46.7 years (range, 17-75 years). The mean duration of the postoperative CSF leak was 3.3 years (range, 3 months to 21 years). MRI showed superficial siderosis in 6 patients. DSM showed the exact location of the CSF leak in 19 (90%) of the 21 patients. These 19 patients all underwent surgery to repair the CSF leak, and the location of the CSF leak could be confirmed intraoperatively in all 19 patients. In 4 (19%) of the 21 patients, DSM also showed a CSF-venous fistula at the same location as the postoperative dural tear.

CONCLUSION: In this study, DSM had a 90% detection rate of visualizing the exact site of the dural breach in patients with extensive postoperative spinal CSF leaks. The coexistence of a CSF-venous fistula in addition to the primary dural tear was present in about one-fifth of patients. The presence of a CSF-venous fistula should be considered if CSF leak symptoms persist in spite of successful repair of a durotomy.

Comparison of Perioperative Complications After Anterior–Posterior Versus Posterior–Anterior–Posterior Cervical Fusion: A Retrospective Review of 153 Consecutive Cases

Neurosurgery 93:373–386, 2023

Although published data support the utilization of circumferential fusion to treat select cervical spine pathologies, it is unclear whether the posterior–anterior–posterior (PAP) fusion has increased risks compared with the anterior–posterior fusion.

OBJECTIVE: To evaluate the differences in perioperative complications between the 2 circumferential cervical fusion approaches.

METHODS: One hundred fifty-three consecutive adult patients who underwent single-staged circumferential cervical fusion for degenerative pathologies from 2010 to 2021 were retrospectively reviewed. Patients were stratified into the anterior–posterior (n = 116) and PAP (n = 37) groups. The primary outcomes assessed were major complications, reoperation, and readmission.

RESULTS: Although the PAP group was older (P = .024), predominantly female (P = .024), with higher baseline neck disability index (P = .026), cervical sagittal vertical axis (P = .001), and previous cervical operation rate (P < .00001), the major complication, reoperation, and readmission rates were not significantly different from the 360°group. Although the PAP group had higher urinary tract infection (P = .043) and transfusion (P = .007) rates, higher estimated blood loss (P = .034), and longer operative times (P < .00001), these differences were insignificant after the multivariable analysis. Overall, operative time was associated with older age (odds ratio [OR] 17.72, P = .042), atrial fibrillation (OR 158.30, P = .045), previous cervical operation (OR 5.05, P = .051), and lower baseline C1-7 lordosis (OR 0.93, P = .007). Higher estimated blood loss was associated with older age (OR 1.13, P = .005), male gender (OR 323.31, P = .047), and higher baseline cervical sagittal vertical axis (OR 9.65, P = .022).

CONCLUSION: Despite some differences in preoperative and intraoperative variables, this study suggests both circumferential approaches have comparable reoperation, readmission, and complication profiles, all of which are high.

Incidence and Risk Factor of Implant Dislocation After Cervical Disk Arthroplasty: A Retrospective Cohort Analysis of 756 Patients

Neurosurgery 93:330–338, 2023

Implant dislocation after cervical disk arthroplasty (CDA) is obviously a critical complication, but no information about the incidence and associated risk factor has been reported.

OBJECTIVE: To investigate the incidence and risk factor of implant dislocation after CDA by a retrospective cohort analysis.

METHODS: A retrospective review of a consecutive series of CDA performed between January 2009 and March 2021 at a single institution was conducted. Analyses of chart records and radiological data established the incidence and associated risk factor of implant dislocation after CDA. A Kaplan-Meier survival estimation of implant survival was performed.

RESULTS: A total of 756 consecutive patients were included in this analysis. Five patients (0.7%) had a migration and even dropout of the artificial disk. The overall cumulative survival rate of the implant reached approximately 99.3% of the 756 patients. Preoperative kyphosis was significantly related to implant dislocation (P = .016), with an odds ratio of 15.013.

CONCLUSION: The incidence of implant dislocation after CDA is as low as 0.7% or 5/756 patients. Preoperative kyphosis significantly increases the risk of postoperative implant dislocation by a factor of 15. The migrating implants could be revealed on radiographs as early as 0.9 to 1.4 months postoperatively and were revised to anterior cervical diskectomy and fusion within half a year. No new event of implant dislocation occurred half a year postoperatively. The overall cumulative survival rate of the implant reached 99.3% of the 756 patients. In conclusion, CDA remains a safe and reliable procedure.

Asymptomatic Postoperative Cerebral Venous Sinus Thrombosis After Posterior Fossa Tumor Surgery: Incidence, Risk Factors, and Therapeutic Options

Neurosurgery 92:1171–1176, 2023

Cerebral venous sinus thrombosis (CVST) is a known complication of posterior fossa surgery near the sigmoid and transverse sinus. The incidence and treatment of postoperative asymptomatic CVST are controversial.

OBJECTIVE: To analyze incidence, risk factors, and management of asymptomatic postoperative CVST after posterior fossa tumor surgery.

METHODS: In this retrospective, single-center study, we included all patients who underwent posterior fossa tumor surgery in the semisitting position between January 2013 and December 2020. All patients underwent preoperative and postoperative imaging using MRI with/without additional computed tomography angiography. We analyzed the effect of demographic and surgical data on the incidence of postoperative CVST. Furthermore, therapeutic anticoagulation or conservative treatment for postoperative CVST and the incidence of intracranial hemorrhage were investigated.

RESULTS: In total, 266 patients were included. Thirty-three of 266 (12.4%) patients developed postoperative CVST. All patients were asymptomatic. Thirteen of 33 patients received therapeutic anticoagulation, and 20 patients did not. Univariate analysis showed that age (P= .56), sex (P = .20), American Society of Anesthesiology status (P = .13), body mass index (P = .60), and length of surgery (P= .176) were not statistically correlated with postoperative CVST. Multivariate analysis revealed that meningioma (P < .001, odds ratio 11.3, CI 95% 4.1-31.2) and vestibular schwannoma (P = .013, odds ratio 4.4, CI 95% 1.3-16.3) are risk factors for the development of new postoperative CVST. The use of therapeutic anticoagulation to treat postoperative CVST was associated with a higher rate of intracranial hemorrhage (n = 4, P = .017).

CONCLUSION: Tumor entity influences the incidence of postoperative CVST. In clinically asymptomatic patients, careful decision making is necessary whether to initiate therapeutic anticoagulation or not.

 

Asymptomatic Postoperative Cerebral Venous Sinus Thrombosis After Posterior Fossa Tumor Surgery: Incidence, Risk Factors, and Therapeutic Options

Neurosurgery 92:1171–1176, 2023

Cerebral venous sinus thrombosis (CVST) is a known complication of posterior fossa surgery near the sigmoid and transverse sinus. The incidence and treatment of postoperative asymptomatic CVST are controversial.

OBJECTIVE: To analyze incidence, risk factors, and management of asymptomatic postoperative CVST after posterior fossa tumor surgery.

METHODS: In this retrospective, single-center study, we included all patients who underwent posterior fossa tumor surgery in the semisitting position between January 2013 and December 2020. All patients underwent preoperative and postoperative imaging using MRI with/without additional computed tomography angiography. We analyzed the effect of demographic and surgical data on the incidence of postoperative CVST. Furthermore, therapeutic anticoagulation or conservative treatment for postoperative CVST and the incidence of intracranial hemorrhage were investigated.

RESULTS: In total, 266 patients were included. Thirty-three of 266 (12.4%) patients developed postoperative CVST. All patients were asymptomatic. Thirteen of 33 patients received therapeutic anticoagulation, and 20 patients did not. Univariate analysis showed that age (P= .56), sex (P = .20), American Society of Anesthesiology status (P = .13), body mass index (P = .60), and length of surgery (P= .176) were not statistically correlated with postoperative CVST. Multivariate analysis revealed that meningioma (P < .001, odds ratio 11.3, CI 95% 4.1-31.2) and vestibular schwannoma (P = .013, odds ratio 4.4, CI 95% 1.3-16.3) are risk factors for the development of new postoperative CVST. The use of therapeutic anticoagulation to treat postoperative CVST was associated with a higher rate of intracranial hemorrhage (n = 4, P = .017).

CONCLUSION: Tumor entity influences the incidence of postoperative CVST. In clinically asymptomatic patients, careful decision making is necessary whether to initiate therapeutic anticoagulation or not.

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.

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