Tag: minimally invasive

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Midline lumbar interbody fusion: a review of the surgical technique and outcomes

J Neurosurg Spine 39:462–470, 2023

Midline lumbar interbody fusion (MidLIF) is a mini-open posterior interbody fusion technique defined by a cortical screw trajectory wherein screws are placed from a more medial to lateral trajectory compared with traditional pedicle screws. This enables the surgeon to perform a smaller muscle dissection with the benefits of improved blood loss, less muscle retraction, decreased operative time, shorter length of stay, and improved back pain outcomes compared with the traditional posterior lumbar interbody fusion techniques utilizing pedicle screw fixation.

Importantly, MidLIF offers comparable clinical outcomes and radiographic outcomes to other posterior lumbar interbody fusion techniques.

In the current review, the authors aimed to educate readers about the MidLIF surgical technique, as well as surgical, clinical, radiographic, cost effectiveness, and biomechanical outcomes, when compared with both open and minimally invasive posterior lumbar interbody fusion techniques with pedicle screw fixation.

Readers will be able to utilize this information to determine how the MidLIF procedure compares as an alternative to traditional techniques.

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Minimally Invasive Transforaminal Lumbar Interbody Fusion in the Ambulatory Surgery Center Versus Inpatient Setting: A 1-Year Comparative Effectiveness Analysis

Neurosurgery 93:867–874, 2023

Ambulatory surgery centers (ASCs) have emerged as an alternative setting for surgical care as part of the national effort to lower health care costs. The literature regarding the safety of minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) in the ASC setting is limited to few small case series.

OBJECTIVE: To assess the safety and efficacy of MIS TLIF performed in the ASC vs inpatient hospital setting.

METHODS: A total of 775 patients prospectively enrolled in the Quality Outcomes Database undergoing single-level MIS TLIF at a single ASC (100) or the inpatient hospital setting (675) were compared. Propensity matching generated 200 patients for analysis (100 per cohort). Demographic data, resource utilization, patient-reported outcome measures (PROMs), and patient satisfaction were assessed.

RESULTS: There were no significant differences regarding baseline demographic data, clinical history, or comorbidities after propensity matching. Only 1 patient required inpatient transfer from the ASC because of intractable pain. All other patients were discharged home within 23 hours of surgery. The rates of 90-day readmission (2.0%) and reoperation (0%) were equivalent between groups. Both groups experienced significant improvements in all PROMs (Oswestry Disability Index, EuroQol-5D, back pain, and leg pain) at 3 months that were maintained at 1 year. PROMs did not differ between groups at any time point. Patient satisfaction was similar between groups at 3 and 12 months after surgery.

CONCLUSION: In carefully selected patients, MIS TLIF may be performed safely in the ASC setting with no statistically significant difference in safety or efficacy in comparison with the inpatient setting.

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Surgical Resection of Deep-Seated Arteriovenous Malformations Through Stereotactically Guided Tubular Retractor Systems

Operative Neurosurgery 24:499–506, 2023

Arteriovenous malformations (AVMs) in the subcortical and/or periventricular regions can cause significant intraventricular and intracranial hemorrhage. These AVMs can pose a unique surgical challenge because traditional, open approaches to the periventricular region require significant cortical/white matter retraction to establish sufficient operative corridors, which may result in risk of neurological injury. Minimally invasive tubular retractor systems represent a novel, feasible surgical option for treating deep-seated AVMs.

OBJECTIVE: To explore 5 cases of NICO BrainPath-assisted resection of subcortical/ periventricular AVMs.

METHODS: Five patients from a single institution were operated on for deep-seated AVMs using tubular retractor systems. Collected data included demographics, AVM specifications, preoperative neurological status, postoperative neurological status, and postoperative/intraoperative angiogram results.

RESULTS: Five patients, ranging from age 10 to 45 years, underwent mini-craniotomy for stereotactically guided tubular retractor-assisted AVM resection using neuronavigation for selecting a safe operative corridor. No preoperative embolization was necessary. Mean maximum AVM nidal diameter was 8.2 mm. All deep-seated AVMs were completely resected without complications. All AVMs demonstrated complete obliteration on intraoperative angiogram and on 6-month follow-up angiogram.

CONCLUSION: Minimally invasive tubular retractors are safe and present a promising surgical option for well-selected deep-seated AVMs. Furthermore, study may elucidate whether tubular retractors improve outcomes after microsurgical AVM resection secondary to mitigation of iatrogenic retraction injury risk.

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Minimally Invasive Preganglionic C2 Root Section for Occipital Neuralgia

Operative Neurosurgery 24:E148–E152, 2023

Occipital neuralgia is a painful condition that is believed to occur from processes that affect the greater, lesser, or third occipital nerves. Diagnosis is often made with a combination of classical symptoms, tenderness over the occipital region, and response to occipital nerve blocks. Cervical computed tomography or MRI may be obtained in multiple positions to detect any impingement. Diagnosis can be made with MRI tractography. Nonsurgical treatments include local anesthetic and steroid injections, anticonvulsant medications, botulinum toxin injections, physical therapy, acupuncture, transcutaneous electrical stimulation, cryoneurolysis, and radiofrequency ablation. Surgical treatments include greater occipital nerve decompression, C2 root section, intradural dorsal root rhizotomy, C1-2 fusion, and occipital nerve stimulation. Although stimulation has been favored in the past decade, complications and maintenance of the devices have led us to return to C2 ganglionectomy.

OBJECTIVE: To report on the use of a minimally invasive technique for C2 ganglionectomy to treat occipital neuralgia.

METHODS: Review demographic, surgery, and outcome data of a minimally invasive C2 root ganglionectomy used to treat to 2 patients with occipital neuralgia.

RESULTS: We report on 2 patients with clinically stereotypical unilateral occipital neuralgia confirmed by greater occipital nerve block, but with no imaging correlate. Both were successfully managed by C2 ganglionectomy through an 18-mm tubular retractor and outpatient surgery. Accompanying text, still photographs, and video describe the technique in detail.

CONCLUSION: Minimally invasive C2 ganglionectomy can be used to successfully treat occipital neuralgia.

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Percutaneous Direct Pars Repair in Young Athletes

Neurosurgery 92:263–270, 2023

Lumbar pars defects are common in adolescent athletes and are often due to recurrent axial loading and traumatic stressors.

OBJECTIVE: To present an updated case series of young athletes who underwent percutaneous direct pars repair after failure of conservative management.

METHODS: A single-center, nonrandomized, retrospective observation study of athletes who were referred for minimally invasive direct pars repair after failure of at least 6 months of conservative management was performed. Summary demographic information, clinical features of presentation, perioperative and intraoperative radiographic imaging, and visual analog scale back pain scores were collected and analyzed.

RESULTS: A total of 21 patients were included (mean age [± SD] 17.47 ± 3.02 years, range 14-25 years), 6 of whom were female (29%). All patients presented with bilateral pars fractures, with L5 being the most frequent level involved (n = 13). The average follow-up time was 31.52 ± 9.38 months (range 3-110 months). The visual analog scale score for back pain was significantly reduced from 7.62 ± 1.83 preoperatively to 0.28 ± 0.56 at the final postoperative examination (P < .01). Fusion was noted in 20 of the 21 patients on final follow-up (95%).

CONCLUSION: Percutaneous direct pars repair is a safe and effective means in treating young adolescents who have failed conservative management. The advantages included minimized muscle and soft tissue dissection, reduced blood loss, and early mobilization and recovery. In young athletes who desire return to high-level physical activity, this surgical technique is of particular benefit and should be considered in this patient population.

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Long-term functional independence after minimally invasive endoscopic intracerebral hemorrhage evacuation

J Neurosurg 138:154–164, 2023

Intracerebral hemorrhage (ICH) is a devastating form of stroke with no proven treatment. However, minimally invasive endoscopic evacuation is a promising potential therapeutic option for ICH. Herein, the authors examine factors associated with long-term functional independence (modified Rankin Scale [mRS] score ≤ 2) in patients with spontaneous ICH who underwent minimally invasive endoscopic evacuation.

METHODS Patients with spontaneous supratentorial ICH who had presented to a large urban healthcare system from December 2015 to October 2018 were triaged to a central hospital for minimally invasive endoscopic evacuation. Inclusion criteria for this study included age ≥ 18 years, hematoma volume ≥ 15 ml, National Institutes of Health Stroke Scale (NIHSS) score ≥ 6, premorbid mRS score ≤ 3, and time from ictus ≤ 72 hours. Demographic, clinical, and radiographic factors previously shown to impact functional outcome in ICH were included in a retrospective univariate analysis with patients dichotomized into independent (mRS score ≤ 2) and dependent (mRS score ≥ 3) outcome groups, according to 6-month mRS scores. Factors that reached a threshold of p < 0.05 in a univariate analysis were included in a multivariate logistic regression.

RESULTS A total of 90 patients met the study inclusion criteria. The median preoperative hematoma volume was 41 (IQR 27–65) ml and the median postoperative volume was 1.2 (0.3–7.5) ml, resulting in a median evacuation percentage of 97% (85%–99%). The median hospital length of stay was 17 (IQR 9–25) days, and 8 (9%) patients died within 30 days of surgery. Twenty-four (27%) patients had attained functional independence by 6 months. Factors independently associated with long-term functional independence included lower NIHSS score at presentation (OR per point 0.78, 95% CI 0.67–0.91, p = 0.002), lack of intraventricular hemorrhage (IVH; OR 0.20, 95% CI 0.05–0.77, p = 0.02), and shorter time to evacuation (OR per hour 0.95, 95% CI 0.91–0.99, p = 0.007). Specifically, patients who had undergone evacuation within 24 hours of ictus demonstrated an mRS score ≤ 2 rate of 36% and were associated with an increased likelihood of long-term independence (OR 17.7, 95% CI 1.90–164, p = 0.01) as compared to those who had undergone evacuation after 48 hours.

CONCLUSIONS In a single-center minimally invasive endoscopic ICH evacuation cohort, NIHSS score on presentation, lack of IVH, and shorter time to evacuation were independently associated with functional independence at 6 months. Factors associated with functional independence may help to better predict populations suitable for minimally invasive endoscopic evacuation and guide protocols for future clinical trials.

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Comparison of local and regional radiographic outcomes in minimally invasive and open TLIF

J Neurosurg Spine 37:384–394, 2022

Local and regional radiographic outcomes following minimally invasive (MI) transforaminal lumbar interbody fusion (TLIF) versus open TLIF remain unclear. The purpose of this study was to provide a comprehensive assessment of local and regional radiographic parameters following MI-TLIF and open TLIF. The authors hypothesized that open TLIF provides greater segmental and global lordosis correction than MI-TLIF.

METHODS A single-center retrospective cohort study of consecutive patients undergoing MI- or open TLIF for grade I degenerative spondylolisthesis was performed. One-to-one nearest-neighbor propensity score matching (PSM) was used to match patients who underwent open TLIF to those who underwent MI-TLIF. Sagittal segmental radiographic measures included segmental lordosis (SL), anterior disc height (ADH), posterior disc height (PDH), foraminal height (FH), percent spondylolisthesis, and cage position. Lumbopelvic radiographic parameters included overall lumbar lordosis (LL), pelvic incidence (PI)–lumbar lordosis (PI-LL) mismatch, sacral slope (SS), and pelvic tilt (PT). Change in segmental or overall lordosis after surgery was considered “lordosing” if the change was > 0° and “kyphosing” if it was ≤ 0°. Student t-tests or Wilcoxon rank-sum tests were used to compare outcomes between MI-TLIF and open-TLIF groups.

RESULTS A total of 267 patients were included in the study, 114 (43%) who underwent MI-TLIF and 153 (57%) who underwent open TLIF, with an average follow-up of 56.6 weeks (SD 23.5 weeks). After PSM, there were 75 patients in each group. At the latest follow-up both MI- and open-TLIF patients experienced significant improvements in assessment scores obtained with the Oswestry Disability Index (ODI) and the numeric rating scale for low-back pain (NRS-BP), without significant differences between groups (p > 0.05). Both MI- and open-TLIF patients experienced significant improvements in SL, ADH, and percent corrected spondylolisthesis compared to baseline (p < 0.001). However, the MI-TLIF group experienced significantly larger magnitudes of correction with respect to these metrics (ΔSL 4.14° ± 4.35° vs 1.15° ± 3.88°, p < 0.001; ΔADH 4.25 ± 3.68 vs 1.41 ± 3.77 mm, p < 0.001; percent corrected spondylolisthesis: −10.82% ± 6.47% vs −5.87% ± 8.32%, p < 0.001). In the MI-TLIF group, LL improved in 44% (0.3° ± 8.5°) of the cases, compared to 48% (0.9° ± 6.4°) of the cases in the open-TLIF group (p > 0.05). Stratification by operative technique (unilateral vs bilateral facetectomy) and by interbody device (static vs expandable) did not yield statistically significant differences (p > 0.05).

CONCLUSIONS Both MI- and open-TLIF patients experienced significant improvements in patient-reported outcome (PRO) measures and local radiographic parameters, with neutral effects on regional alignment. Surprisingly, in our cohort, change in SL was significantly greater in MI-TLIF patients, perhaps reflecting the effect of operative techniques, technological innovations, and the preservation of the posterior tension band. Taking these results together, no significant overall differences in LL between groups were demonstrated, which suggests that MI-TLIF is comparable to open approaches in providing radiographic correction after surgery. These findings suggest that alignment targets can be achieved by either MI- or open-TLIF approaches, highlighting the importance of surgeon attention to these variables.

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Minimally Invasive Transforaminal Lumbar Interbody Fusion: Cost of a Surgeon’s Learning Curve

World Neurosurg. (2022) 162:e1-e7

Minimally invasive transforaminal interbody fusion has become an increasingly common approach in adult degenerative spine disease but is associated with a steep learning curve. We sought to evaluate the impact of the learning experience on mean procedure time and mean cost associated with each procedure.

METHODS: We studied the first 100 consecutive minimally invasive transforaminal interbody fusion procedures of a single surgeon. We performed multivariable linear regression models, modeling operating time, and costs in function of the procedure order adjusted for patients’ age, sex, and number of surgical levels. The number of procedures necessary to attain proficiency was determined through a k-means cluster analysis. Finally, the total excess operative time and total excess cost until obtaining proficiency was evaluated.

RESULTS: Procedure order was found to impact procedure time and mean costs, with each successive case being associated with progressively less procedure time and cost. On average, each successive case was associated with a reduction in procedure time of 0.97 minutes (95% confidence interval 0.54e1.40; P < 0.001) and an average adjusted reduction in overall costs of $82.75 (95% confidence interval $35.93e129.57; P < 0.001). An estimated 58 procedures were needed to attain proficiency, translating into an excess procedure time of 2604.2 minutes (average of 45 minutes per case), overall costs associated with the learning experience of $226,563.8 (average of $3974.80 per case), and excess surgical cost of $125,836.6 (average of $2207.66 per case).

CONCLUSIONS: Successive cases were associated with progressively less procedure time and mean overall and surgical costs, until a proficiency threshold was attained.

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Supraorbital and mini-pterional keyhole craniotomies for brain tumors

J Neurosurg 136:1314–1324, 2022

The authors’ objective was to compare the indications, outcomes, and anatomical limits of supraorbital (SO) and mini-pterional (MP) craniotomies in patients with intra- and extraaxial brain tumors, and to assess approach selection, utility of endoscopy, and surgical field overlap.

METHODS A retrospective analysis was conducted of all brain tumor patients who underwent an SO or MP approach. The analyzed characteristics included pathology, endoscopy use, extent of resection, length of stay (LOS), and complications. On the basis of preoperative MRI data, tumor heatmaps were constructed to compare surgical access provided by both routes, including coronal projection heatmaps for parasellar tumors.

RESULTS From 2007 to 2020, 158 patients underwent 173 (84.8%) SO craniotomies and 30 patients underwent 31 (15.2%) MP craniotomies; 71 (34.8%) procedures were reoperations. Of these 204 operations, 110 (63.6%) SO and 21 (67.7%) MP approaches were for extraaxial tumors (meningiomas in 65% and 76.2%, respectively). Gliomas and metastases together represented 84.1% and 70% of intraaxial tumors accessed with SO and MP approaches, respectively. Overall, 56.1% of tumors accessed with the SO approach and 41.9% of those accessed with the MP approach were in the parasellar region. Axial projection heatmaps showed that SO access extended along the entire ipsilateral and medial contralateral anterior cranial fossa, parasellar region, ipsilateral sylvian fissure, medial middle cranial fossa, and anterior midbrain, whereas MP access was limited to the ipsilateral middle cranial fossa, sylvian fissure, lateral parasellar region, and posterior aspect of anterior cranial fossa. Coronal projection heatmaps showed that parasellar access extended further superiorly with the SO approach compared with that of the MP approach. Endoscopy was utilized in 98 (56.6%) SO craniotomies and 7 (22.6%) MP craniotomies, with further tumor resection in 48 (49%) and 5 (71.4%) cases, respectively. Endoscope-assisted tumor removal was clustered in areas that were generally at farther distances from the craniotomy or in angled locations such as the cribriform plate region where microscopic visualization is limited. Gross-total or neartotal resection was achieved in 120/173 (69%) SO approaches and 21/31 (68%) MP approaches. Major complications occurred in 11 (6.4%) SO approaches and 1 (3.2%) MP approach (p = 0.49). The median LOS decreased to 2 days in the last 2 years of the study.

CONCLUSIONS This clinical experience suggests the SO and MP craniotomies are versatile, safe, and complementary approaches for tumors located in the anterior and middle cranial fossae and perisylvian and parasellar regions. The SO route, used in 85% of cases, achieved greater overall reach than the MP route. Both approaches may benefit from expanded visualization with endoscopy.

 

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Robotic-Assisted vs Nonrobotic-Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Cost-Utility Analysis

Neurosurgery 90:192–198, 2022

Management of degenerative disease of the spine has evolved to favor minimally invasive techniques, including nonrobotic-assisted and robotic-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). Value-based spending is being increasingly implemented to control rising costs in the US healthcare system. With an aging population, it is fundamental to understand which procedure(s) may be most cost-effective.

OBJECTIVE: To compare robotic and nonrobotic MIS-TLIF through a cost-utility analysis.

METHODS: We considered direct medical costs related to surgical intervention and to the hospital stay, as well as 1-yr utilities. We estimated costs by assessing all cases involving adults undergoing robotic surgery at a single institution and an equal number of patients undergoing nonrobotic surgery, matched by demographic and clinical characteristics. We adopted a willingness to pay of $50 000/quality-adjusted life year (QALY). Uncertainty was addressed by deterministic and probabilistic sensitivity analyses.

RESULTS: Costs were estimated based on a total of 76 patients, including 38 undergoing robot-assisted and 38 matched patients undergoing nonrobot MIS-TLIF. Using point estimates, robotic surgery was projected to cost $21 546.80 and to be associated with 0.68 QALY, and nonrobotic surgery was projected to cost $22 398.98 and to be associated with 0.67 QALY. Robotic surgery was found to be more cost-effective strategy, with costeffectiveness being sensitive operating room/materials and room costs. Probabilistic sensitivity analysis identified robotic surgery as cost-effective in 63% of simulations.

CONCLUSION: Our results suggest that at a willingness to pay of $50 000/QALY, robotic assisted MIS-TLIF was cost-effective in 63% of simulations. Cost-effectiveness depends on operating room and room (admission) costs, with potentially different results under distinct neurosurgical practices.

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Magnetic Resonance Imaging-Guided Stereotactic Laser Ablation of Deep Cerebral Cavernous Malformations

Neurosurgery 89:635–644, 2021

Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (MRgLITT) has been used successfully to treat epileptogenic cortical cerebral cavernous malformations (CCM). It is unclear whether MRgLITT would be as feasible or safe for deep CCMs

OBJECTIVE: To describe our experience with MRgLITT for symptomatic deep CCMs

METHODS: Patients’records were reviewed retrospectively. MRgLITT was carried out using a commercially available system in an interventional MRI suite with efforts to protect adjacent brain structures. Immediate postoperative imaging was used to judge ablation adequacy. Delayed postoperative MRI was used to measure lesion volume changes during follow-up.

RESULTS: Four patients with CCM in the thalamus, putamen, midbrain, or subthalamus presented with persistent and disabling neurological symptoms. A total of 2 patients presented with disabling headaches and sensory disturbances and 2 with recurrent symptomatic hemorrhages, of which 1 had familial CCM. Patients were considered by vascular neurosurgeons to be poor candidates for open surgery or had refused it. Multiple trajectories were used in most cases. Adverse events included device malfunction with leakage of saline causing transient mass effect in one patient, and asymptomatic tract hemorrhage in another. One patient suffered an expected mild but persistent exacerbation of baseline deficits. All patients showed improvement from a previously aggressive clinical course with lesion volume decreased by 20% to 73% in follow-up.

CONCLUSION: MRgLITT is feasible in the treatment of symptomatic deep CCM but may carry a high risk of complications without the benefit of definitive resection. We recommend cautious patient selection, low laser power settings, and conservative temper- ature monitoring in surrounding brain parenchyma.

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Safety of lateral access to the concave side for adult spinal deformity

J Neurosurg Spine 35:100–104, 2021

Minimally invasive surgery (MIS) techniques, particularly lateral lumbar interbody fusion (LLIF), have become increasingly popular for adult spinal deformity (ASD) correction. Much discussion has been had regarding theoretical and clinical advantages to addressing coronal curvature from the convex versus concave side of the curve. In this study, the authors aimed to broadly evaluate the clinical outcomes of addressing ASD with circumferential MIS (cMIS) techniques while accessing the lumbar coronal curvature from the concave side.

METHODS A multi-institution, retrospective chart and radiographic review was performed for all ASD patients with at least a 10° curvature, as defined by the Scoliosis Research Society, who underwent cMIS correction. The data collected included convex versus concave access to the coronal curve, durable or sensory femoral nerve injury lasting longer than 6 weeks, vascular injury, visceral injury, and any additional major complication, with at least a 2-year follow-up. Neither health-related quality-of-life metrics nor spinopelvic parameters were included within the scope of this study.

RESULTS A total of 152 patients with ASD treated with cMIS correction via lateral access were identified and analyzed. Of these, 126 (82.9%) were approached from the concave side and 26 (17.1%) were approached from the convex side. In the concave group, 1 (0.8%) motor and 4 (3.2%) sensory deficit cases remained at 6 weeks after the operation. No vascular, visceral, or catastrophic intraoperative injuries were encountered in the concave group. Of the 26 patients in the convex group, 2 (7.7%) experienced motor deficits lasting longer than 6 weeks and 5 (19.2%) had lower-extremity sensory deficits.

CONCLUSIONS It has been reported that lateral access to the convex side is associated with similar clinical and radiographic outcomes with fewer complications when compared with access to the concave side. Advantages to approaching the lumbar spine from the concave side include using one incision to access multiple levels, breaking the operative table to assist with curvature correction, easier access to the L4–5 disc space, the ability to release the contracted side, and, often, avoidance of the need to access or traverse the thoracic cavity. This study illustrates the largest reported cohort of concave access for cMIS scoliosis correction; few postoperative sensory and motor deficits were found.

 

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Coronal balance with circumferential minimally invasive spinal deformity surgery for the treatment of degenerative scoliosis

J Neurosurg Spine 34:879–887, 2021

Coronal malalignment (CM) in adult spinal deformity is associated with poor outcomes and remains underappreciated in the literature. Recent attempts at classifying CM indicate that some coronal shifts may be more difficult to treat than others. To date, outcomes for circumferential minimally invasive surgery (cMIS) of the spine in the context of these new CM classifications are unreported.

METHODS A retrospective evaluation of patients with degenerative scoliosis (Cobb angle > 20 ) consecutively treated with cMIS at a single institution was performed. Preoperative and 1-year postoperative standing radiographs were used to make the comparisons. Clinical outcome measures were compared. Patients were subgrouped according to the preoperative distance between their C7 plumb line and central sacral vertical line (C7-CSVL) as either coronally aligned (type A, C7-CSVL < 3 cm); shifted ≥ 3 cm toward the concavity (type B); or shifted ≥ 3 cm toward the convexity (type C) of the main lumbar curve.

RESULTS Forty-two patients were included (mean age 67.7 years). Twenty-six patients (62%) were classified as type A, 5 patients (12%) as type B, and 11 patients (26%) as type C. An average of 4.9 segments were treated. No type A patients developed postoperative CM. All type B patients had CM correction. Six of the 11 type C patients had CM after surgery. Overall, there was an improvement in the C7-CSVL (from 2.4 to 1.8 cm, p = 0.04). Among subgroups, only type B patients improved (from 4.5 to 0.8 cm, p = 0.002); no difference was seen for type A patients (from 1.2 to 1.4 cm, p = 0.32) or type C patients (from 4.3 to 3.1 cm, p = 0.11). Comparing type C patients with postoperative CM versus those without postoperative CM, patients with CM had worse visual analog scale back scores at 1 year (5 vs 1, p = 0.01). Moreover, they had higher postoperative L4 tilt angles (11  vs 5 , p = 0.01), indicating inadequate correction of the lumbosacral fractional curve.

CONCLUSIONS cMIS improved coronal alignment, curve magnitudes, and clinical outcomes among patients with degenerative scoliosis. It did not result in CM in type A patients and was successful at improving the C7-CSVL in type B patients. Type C patients remain the most difficult to treat coronally, with worse visual analog scale back pain scores in those with postoperative CM. Regional coronal restoration of the lumbosacral fracture curve should be the focus of correction in cMIS for these patients.

 

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Minimally Invasive Intracerebral Hematoma Evacuation Using a Novel Cost-Effective Tubular Retractor

World Neurosurg. (2021) 150:42-53

Spontaneous intracerebral hematoma (ICH) is a common disease with a dismal overall prognosis. Recent development of minimally invasive ICH evacuation techniques has shown promising results. Commercially available tubular retractors are commonly used for minimally invasive ICH evacuation yet are globally unavailable.

METHODS: A novel U.S. $7 cost-effective, off-the-shelf, atraumatic tubular retractor for minimally invasive intracranial surgery is described. Patients with acute spontaneous ICH underwent microsurgical tubular retractor assisted minimally invasive ICH evacuation using the novel retractor. Patient outcome was retrospectively analyzed and compared with open surgery and with commercial tubular retractors.

RESULTS: Ten adult patients with spontaneous supratentorial ICH and median preoperative Glasgow Coma Scale score of 10 were included. ICH involved the frontal lobe, parietal lobe, occipitotemporal region, and solely basal ganglia in 3, 3, 2, and 2 patients, respectively. Mean preoperative ICH volume was 80 mL. Mean residual hematoma volume was 8.7 mL and mean volumetric hematoma reduction was 91% (median, 94%). Seven patients (70%) underwent >90% volumetric hematoma reduction. The total median length of hospitalization was 26 days. On discharge, the median Glasgow Coma Scale score was 12.5 (mean, 11.7). Thirty to 90 days’ follow-up data were available for 9 patients (90%). The mean follow-up modified Rankin Scale score was 3.7 and 5 patients (56%) had a modified Rankin Scale score of 3.

CONCLUSIONS: The novel cost-effective tubular retractor and microsurgical technique offer a safe and effective method for minimally invasive ICH evacuation. Cost-effective tubular retractors may continue to present a valid alternative to commercial tubular retractors.

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Comparative anatomical analysis between the minipterional and supraorbital approaches

J Neurosurg 134:1276–1284, 2021

Keyhole approaches, namely the minipterional approach (MPTa) and the supraorbital approach (SOa), are alternatives to the standard pterional approach to treat lesions located in the anterior and middle cranial fossae. Despite their increasing popularity and acceptance, the indications and limitations of these approaches require further assessment. The purpose of the present study was to determine the differences in the area of surgical exposure and surgical maneuverability provided by the MPTa and SOa.

METHODS The areas of surgical exposure afforded by the MPTa and SOa were analyzed in 12 sides of cadaver heads by using a microscope and a neuronavigation system. The area of exposure of the region of interest and surgical freedom (maneuverability) of each approach were calculated.

RESULTS The area of exposure was significantly larger in the MPTa than in the SOa (1250 ± 223 mm2 vs 939 ± 139 mm2, p = 0.002). The MPTa provided larger areas of exposure in the ipsilateral and midline compartments, whereas there was no significant difference in the area of exposure in the contralateral compartment. All targets in the anterior circulation had significantly larger areas of surgical freedom when treated via the MPTa versus the SOa.

CONCLUSIONS The MPTa provides greater surgical exposure and better maneuverability than that offered by the SOa. The SOa may be advantageous as a direct corridor for treating lesions located in the contralateral side or in the anterior cranial fossa, but the surgical exposure provided in the midline region is inferior to that exposed by the MPTa.

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Eyebrow supraorbital keyhole craniotomy for olfactory groove meningiomas with endoscope assistance

Acta Neurochirurgica (2021) 163:101–112

Olfactory groove meningiomas (OGMs) are commonly treated with open craniotomy. Endonasal approaches have also been described. Objective To present clinical and radiographic outcomes for the minimally invasive eyebrow incision supraorbital keyhole approach with endoscopic assistance for OGMs.

Methods We performed a retrospective single-center cohort study and a systematic literature review.

Results Fifteen patients were identified, all with Grade I meningiomas. Radiographic gross total resection of enhancing tumor was achieved in all patients. Mean frontal lobe fluid-attenuated inversion recovery volume decreased from 11.1 ± 18.3 cm3 preoperatively to 9.9 ± 11.4 cm3 immediately postoperatively, and there was minimal new restricted diffusion (3.2 ± 2.2 cm3; max 7.5 cm3). Median length of stay was 3 days (range 2–8). Vision was improved in 4 (80%) and stable in 1 (20%) of 5 patients with a preoperative deficit. New postoperative anosmia occurred in 3 (23%) of 13 patients with any preoperative olfaction. All patients were satisfied with their cosmetic result at 3 months. After a median follow-up of 32.2 months, there were 2 (13.3%) asymptomatic radiographic recurrences, 1 treated with radiosurgery and the other with endoscopic endonasal approach (EEA). No patients required further craniotomy. Systematic review revealed the present series to be the largest to date reporting disaggregated outcomes for the eyebrow approach to OGM.

Conclusion The eyebrow incision supraorbital keyhole craniotomy with endoscopic assistance is a safe and effective approach to OGM with tumor control rates similar to more invasive open approaches and better than the endonasal approach.Rates of frontal lobe injury, CSF leak and anosmia are comparatively low.

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Predictors of the Best Outcomes Following Minimally Invasive Surgery for Grade 1 Degenerative Lumbar Spondylolisthesis

Neurosurgery, 87 (6) 2020: 1130–1138

The factors driving the best outcomes following minimally invasive surgery (MIS) for grade 1 degenerative lumbar spondylolisthesis are not clearly elucidated.

OBJECTIVE: To investigate the factors that drive the best 24-mo patient-reported outcomes (PRO) following MIS surgery for grade 1 degenerative lumbar spondylolisthesis.

METHODS: A total of 259 patients from the Quality Outcomes Database lumbar spondylolisthesis module underwent single-level surgery for degenerative grade 1 lumbar spondylolisthesis with MIS techniques (188 fusions, 72.6%). Twenty-four-month follow-up PROs were collected and included the Oswestry disability index (ODI) change (ie, 24-mo minus baseline value), numeric rating scale (NRS) back pain change, NRS leg pain change, EuroQoL-5D (EQ-5D) questionnaire change, and North American Spine Society (NASS) satisfaction questionnaire. Multivariable models were constructed to identify predictors of PRO change.

RESULTS: The mean age was 64.2 ± 11.5 yr and consisted of 148 (57.1%) women and 111(42.9%) men. In multivariable analyses, employment was associated with superior postoperative ODI change (β-7.8; 95% CI [−12.9 to −2.6]; P = .003), NRS back pain change (β −1.2; 95% CI [−2.1 to −0.4]; P = .004), EQ-5D change (β 0.1; 95% CI [0.01-0.1]; P = .03), and NASS satisfaction (OR = 3.7; 95% CI [1.7-8.3]; P < .001). Increasing age was associated with superior NRS leg pain change (β −0.1; 95% CI [−0.1 to −0.01]; P= .03) and NASS satisfaction (OR=1.05; 95%CI [1.01-1.09]; P=.02). Fusion surgerieswere associated with superior ODI change (β −6.7; 95% CI [−12.7 to −0.7]; P= .03), NRS back pain change (β −1.1; 95% CI [−2.1 to −0.2]; P= .02), and NASS satisfaction (OR = 3.6; 95% CI [1.6-8.3]; P= .002).

CONCLUSION: Preoperative employment and surgeries, including a fusion, were predictors of superior outcomes across the domains of disease-specific disability, back pain, leg pain, quality of life, and patient satisfaction. Increasing age was predictive of superior outcomes for leg pain improvement and satisfaction.

 

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Minimally invasive posterior percutaneous transarticular C1–C2 screws: how I do it

Acta Neurochirurgica (2020) 162:2047–2050

Transarticular C1–C2 screw fixation, first described by Magerl, is a widely accepted used technique for C1–C2 instability with a good biomechanical stability and fusion rate.

Method We present a 69-year-old woman, who was diagnosed with a C2 Odontoid fracture type III and primarily treated with conservative treatment and collar. During first 2 weeks of follow-up, the patient developed cervical pain associated with C1–C2 instability. A minimally invasive posterior C1–C2 transarticular screw instrumentation with a percutaneus approach was performed.

Results and conclusion Minimally invasive approach with tubular transmuscular approach for C1–C2 transarticular screws instrumentation is safe and effective for C1–C2 instability.

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Anterior Column Realignment: Analysis of Neurological Risk and Radiographic Outcomes

Neurosurgery DOI:10.1093/neuros/nyaa064

Anterior column realignment (ACR) is a less invasive alternative to 3-column osteotomy for the correction of sagittal imbalance. We hypothesized that ACR would correct sagittal imbalance with an acceptable neurological risk. OBJECTIVE: To assess long-term neurological and radiographic outcomes after ACR.

METHODS: Patients ≥18 yr who underwent ACR from 2005 to 2013 were eligible. Standing scoliosis radiographs were studied at preoperation, postoperation (≤6 wk), and at minimum 2 yr of follow-up. Clinical/radiographic data were collected through a retrospective chart review, with thoracic 1 spino-pelvic inclination (T1SPi) used as the angular surrogate for sagittal vertical axis.

RESULTS: A total of 26 patients had complete data, with a mean follow-up of 2.8 yr (1.8- 7.4). Preoperative, sagittal parameters were lumbar lordosis (LL) of −16.1◦, pelvic incidence (PI)-LL of 41.7◦, T1SPi of 3.6◦, and pelvis tilt (PT) of 32.4◦. LL improved by 30.6◦ (P < .001) postoperation.Mean changes in PT (−8.3), sacral slope (8.9), T1SPi (−4.9), and PI-LL (−33.5) were all significant. The motion segment angle improved by 26.6◦, from 5.2◦ to −21.4◦ (P < .001). Neurological complications occurred in 32% patients postoperation (n = 8; 1 patient with both sensory and motor). New thigh numbness/paresthesia developed in 3 (13%) patients postoperation; only 1 (4%) persisted at latest follow-up. A total of 6 (24%) patients developed a new lower extremity motor deficit postoperation,with 4 (8%) having persistent new weakness at last follow-up. Out of 8 patients with preoperative motor deficit, half saw improvement postoperation and 75% improved by last follow-up.

CONCLUSION: There was net motor improvement, with 24% of patients improving and 16% having persistent new weakness at latest follow-up; 60% were unchanged. Radiographic results demonstrate that ACR is a useful tool to treat severe sagittal plane deformity.

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Intermediate-term clinical and radiographic outcomes with less invasive adult spinal deformity surgery

Acta Neurochirurgica (2020) 162:1393–1400

Little information exists regarding longer-term outcomes with minimally invasive spine surgery (MISS), particularly regarding long-segment and deformity procedures. We aimed to evaluate intermediate-term outcomes of MISS for adult spinal deformity (ASD).

Methods This retrospective review of a prospectively collected multicenter database examined outcomes at 4 or more years following circumferential MIS (cMIS) or hybrid (HYB) surgery for ASD. A total of 53 patients at 8 academic centers satisfied the following inclusion criteria: age > 18 years and coronal Cobb > 20°, pelvic incidence-lumbar lordosis (PI-LL) > 10°, or sagittal vertical axis (SVA) > 5 cm.

Results Radiographic outcomes demonstrated improvements of PI-LL from 16.8° preoperatively to 10.8° and coronal Cobb angle from38° preoperatively to 18.2° at 4 years. The incidence of complications over the follow-up periodwas 56.6%.A total of 21 (39.6%) patients underwent reoperation in the thoracolumbar spine, most commonly for adjacent level disease or proximal junctional kyphosis, which occurred in 11 (20.8%) patients. Mean Oswestry Disability Index (ODI) at baseline and years 1 through 4 were 49.9, 33.1, 30.2, 32.7, and 35.0, respectively. The percentage of patients meeting minimal clinically important difference (MCID) (defined as 12% or more from baseline) decreased over time, with leg pain reduction more durable than back pain reduction.

Conclusions Intermediate-term clinical and radiographic improvement following MISS for ASD is sustained, but extent of improvement lessens over time. Outcome variability exists within a subset of patients not meeting MCID, which increases over time after year two. Loss of improvement over time wasmore notable in back than leg pain. However, average ODI improvement meets MCID at 4 years after MIS ASD surgery.

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