Johan Pallud and Emmanuel Mandonnet
Edward F. Chang, Rodney A. Gabriel, Matthew B. Potts, Mitchel S. Berger, and Michael T. Lawton
Resection of cavernous malformations (CMs) located in functionally eloquent areas of the supratentorial compartment is controversial. Hemorrhage from untreated lesions can result in devastating neurological injury, but surgery has potentially serious risks. We hypothesized that an organized system of approaches can guide operative planning and lead to acceptable neurological outcomes in surgical patients.
The authors reviewed the presentation, surgery, and outcomes of 79 consecutive patients who underwent microresection of supratentorial CMs in eloquent and deep brain regions (basal ganglia [in 27 patients], sensorimotor cortex [in 23], language cortex [in 3], thalamus [in 6], visual cortex [in 10], and corpus callosum [in 10]). A total of 13 different microsurgical approaches were organized into 4 groups: superficial, lateral transsylvian, medial interhemispheric, and posterior approaches.
The majority of patients (93.7%) were symptomatic. Hemorrhage with resulting focal neurological deficit was the most common presentation in 53 patients (67%). Complete resection, as determined by postoperative MR imaging, was achieved in 76 patients (96.2%). Overall, the functional neurological status of patients improved after microsurgical dissection at the time of discharge from the hospital and at follow-up. At 6 months, 64 patients (81.0%) were improved relative to their preoperative condition and 14 patients (17.7%) were unchanged. Good outcomes (modified Rankin Scale score ≤ 2, living independently) were achieved in 77 patients (97.4%). Multivariate analysis of demographic and surgical factors revealed that preoperative functional status was the only predictor of postoperative modified Rankin Scale score (OR 4.6, p = 0.001). Six patients (7.6%) had transient worsening of neurological examination after surgery, and 1 patient (1.3%) was permanently worse. There was no surgical mortality.
The authors present a system of 13 microsurgical approaches to 6 location targets with 4 general trajectories to facilitate safe access to supratentorial CMs in eloquent brain regions. Favorable neurological outcomes following microsurgical resection justify an aggressive surgical attitude toward these lesions.
Matthew B. Potts, Jau-Ching Wu, Nalin Gupta, and Praveen V. Mummaneni
Symptomatic tethered cord and associated anomalies such as diastematomyelia rarely present during adulthood but can cause significant pain as well as motor, sensory, and bladder dysfunction. As with children, studies have shown that surgical detethering may provide improvement in pain and neurological deficits. Typical surgical management involves an open laminectomy, sectioning of the filum terminale, and exploration of the split cord malformation. Such open approaches, however, cause significant paraspinous muscle trauma and scarring. Recent advances in minimally invasive techniques allow for access to the spine and thecal sac while minimizing associated muscular trauma. The authors present a comparison of open versus minimally invasive surgery to treat adult tethered cord syndrome.
Six adult patients underwent surgical release of a tethered spinal cord (2 of them also had diastematomyelia). The mean age of the patients was 47.78 years (range 31–64 years). All medical records and images were retrospectively reviewed. Three of the patients underwent traditional open laminectomies for detethering (open group) while the other 3 patients underwent minimally invasive (mini-open) spinal cord detethering. The length of the incision, length of stay, estimated blood loss, and complications were compared between the 2 groups.
All 6 patients had tethered spinal cords, and 1 patient in each group had diastematomyelia. The mean estimated blood loss during surgery (300 ml in the open group vs 167 ml in the mini-open group, p = 0.313) and the mean length of stay (7 days in the open group vs 6.3 days in the mini-open group, p = 0.718) were similar between the 2 groups. The incision length was half as long in the mini-open group versus the open group. However, 1 patient in the mini-open group developed a postoperative pseudomeningocele requiring surgical revision, whereas the open group had no revision surgeries.
Cases of symptomatic diastematomyelia and tethered cord in adults can be safely and effectively explored through a mini-open approach. In this small case series, the authors did find that the mini-open group had an incision that was 50% smaller than the open group, but they did not find a significant clinical difference between the groups.
Matthew B. Potts, Justin S. Smith, Annette M. Molinaro, and Mitchel S. Berger
Low-grade gliomas (LGGs) are rarely diagnosed as an incidental, asymptomatic finding, and it is not known how the early surgical management of these tumors might affect outcome. The purpose of this study was to compare the outcomes of patients with incidental and symptomatic LGGs and determine any prognostic factors associated with those outcomes.
All patients treated by the lead author for an LGG incidentally discovered between 1999 and 2010 were retrospectively reviewed. “Incidental” was defined as a finding on imaging that was obtained for a reason not attributable to the glioma, such as trauma or headache. Primary outcomes included overall survival, progression-free survival (PFS), and malignant PFS. Patients with incidental LGGs were compared with a previously reported cohort of patients with symptomatic gliomas.
Thirty-five patients with incidental LGGs were identified. The most common reasons for head imaging were headache not associated with mass effect (31.4%) and trauma (20%). Patients with incidental lesions had significantly lower preoperative tumor volumes than those with symptomatic lesions (20.2 vs 53.9 cm3, p < 0.001), were less likely to have tumors in eloquent locations (14.3% vs 61.9%, p < 0.001), and had a higher prevalence of females (57.1% vs 36%, p = 0.02). In addition, patients with incidental lesions were also more likely to undergo gross-total resection (60% vs 31.5%, p = 0.001) and had improved overall survival on Kaplan-Meier analysis (p = 0.039, Mantel-Cox test). Progression and malignant progression rates did not differ between the 2 groups. Univariate analysis identified pre- and postoperative volumes as well as the use of motor or language mapping as significant prognostic factors for PFS.
In this retrospective cohort of surgically managed LGGs, incidentally discovered lesions were associated with improved patient survival as compared with symptomatic LGGs, with acceptable surgical risks.
Andrew J. Gogos, Jacob S. Young, Matheus P. Pereira, Ramin A. Morshed, Matthew B. Potts, Shawn L. Hervey-Jumper, and Mitchel S. Berger
Although most patients with low-grade glioma (LGG) present after a seizure, a small proportion is diagnosed after neuroimaging is performed for a sign or symptom unrelated to the tumor. While these tumors invariably grow, some surgeons argue for a watchful waiting approach. Here, the authors report on their experience in the surgical treatment of patients with incidental LGG (iLGG) and describe the neurological outcomes, survival, and complications.
Relevant cases were identified from a prospective registry of patients undergoing glioma resection at the University of California, San Francisco, between 1997 and 2019. Cases were considered iLGG when the lesion was noted on imaging performed for a reason unrelated to the tumor. Demographic, clinical, pathological, and imaging data were extracted from the electronic medical record. Tumor volumes, growth, and extent of resection were calculated from pre- and postoperative volumetric FLAIR sequences.
One hundred thirteen of 657 (17.2%) first-time resections for LGG were for incidental lesions. The most common reasons for the discovery of an iLGG were headaches (without mass effect, 34.5%) or trauma (16.8%). Incidental tumors were no different from symptomatic lesions in terms of laterality or location, but they were significantly smaller (22.5 vs 57.5 cm3, p < 0.0001). There was no difference in diagnosis between patients with iLGG and those with symptomatic LGG (sLGG), incorporating both molecular and pathological data. The median preoperative observation time for iLGG was 3.1 months (range 1 month–12 years), and there was a median growth rate of 3.9 cm3/year. Complete resection of the FLAIR abnormality was achieved in 57% of patients with incidental lesions but only 23.8% of symptomatic lesions (p < 0.001), and the residual volumes were smaller for iLGGs (2.9 vs 13.5 cm3, p < 0.0001). Overall survival was significantly longer for patients with incidental tumors (median survival not reached for patients with iLGG vs 14.6 years for those with sLGG, p < 0.0001). There was a 4.4% rate of neurological deficits at 6 months.
The authors present the largest cohort of iLGGs. Patient age, tumor location, and molecular genetics were not different between iLGGs and sLGGs. Incidental tumors were smaller, a greater extent of resection could be achieved, and overall survival was improved compared to those for patients with sLGG. Operative morbidity and rates of neurological deficit were acceptably low; thus, the authors advocate upfront surgical intervention aimed at maximal safe resection for these incidentally discovered lesions.
Collin J. Larkin, Anastasios G. Roumeliotis, Constantine L. Karras, Nikhil K. Murthy, Maria Fay Karras, Huy Minh Tran, Ketan Yerneni, and Matthew B. Potts
Annually, 20% of all practicing neurosurgeons in the United States are faced with medical malpractice litigation. The average indemnity paid in a closed neurosurgical civil claim is $439,146, the highest of all medical specialties. The majority of claims result from dissatisfaction following spinal surgery, although claims after cranial surgery tend to be costlier. On a societal scale, the increasing prevalence of medical malpractice claims is a catalyst for the practice of defensive medicine, resulting in record-level healthcare costs. Outside of the obvious financial strains, malpractice claims have also been linked to professional disenchantment and career changes for afflicted physicians. Unfortunately, neurosurgical residents receive minimal practical education regarding these matters and are often unprepared and vulnerable to these setbacks in the earlier stages of their careers. In this article, the authors aim to provide neurosurgical residents and junior attendings with an introductory guide to the fundamentals of medical malpractice lawsuits and the implications for neurosurgeons as an adjunct to more formal residency education.
R. Shane Tubbs, Matthew R. Levin, Marios Loukas, Eric A. Potts, and Aaron A. Cohen-Gadol
To date, only scant descriptions of the cluneal nerves are available. As these nerves, and especially the superior group, may be encountered and injured during posterior iliac crest harvest for spinal arthrodesis procedures, the present study was performed to better elucidate their anatomy and to provide anatomical landmarks for their localization.
The superior and middle cluneal nerves were dissected from their origin to termination in 20 cadaveric sides. The distance between the posterior superior iliac spine (PSIS) and superior cluneal nerves at the iliac crest and the distance between this bony prominence and the origin of the middle cluneals were measured. The specific course of each nerve was documented, and the diameter and length of all cluneal nerves were measured.
Superior and middle cluneal nerves were found on all sides. An intermediate superior cluneal nerve and lateral superior cluneal nerve were not identified on 4 and 5 sides, respectively. The superior cluneal nerves always passed through the psoas major and paraspinal muscles and traveled posterior to the quadratus lumborum. The mean diameters of the superior and middle cluneal nerves were 1.1 and 0.8 mm, respectively. From the PSIS, the superior cluneal branches passed at means of 5, 6.5, and 7.3 cm laterally on the iliac crest. At their origin, the middle cluneal nerves had mean distances of 2 cm superior to the PSIS, 0 cm from the PSIS, and 1.5 cm inferior to the PSIS. In their course, the middle cluneal nerves traversed the paraspinal muscles attaching onto the dorsal sacrum.
Knowledge of the cutaneous nerves that cross the posterior aspect of the iliac crest may assist in avoiding their injury during bone harvest. Additionally, an understanding of the anatomical pathway that these nerves take may be useful in decompressive procedures for entrapment syndromes involving the cluneal nerves.
Matthew B. Potts, Daniel W. Zumofen, Eytan Raz, Peter K. Nelson, and Howard A. Riina
Endovascular embolization is typically reserved as an adjuvant therapy in the management of cerebral arteriovenous malformations (AVMs), either for preoperative devascularization or preradiosurgical volume reduction. Curative embolization plays a limited role in AVM treatment but several studies have shown that it is possible, especially with later-generation liquid embolic agents. Given the complexity of AVM anatomy and the recent controversies over the role of any intervention in AVM management, it is critical that the cerebrovascular community better define the indications of each treatment modality to provide quality AVM management. In this review, the authors evaluate the role of curative AVM embolization. Important considerations in the feasibility of curative AVM embolization include whether it can be performed reliably and safely, and whether it is a durable cure. Studies over the past 20 years have begun to define the anatomical factors that are amenable to complete endovascular occlusion, including size, feeding artery anatomy, AVM morphology, and endovascular accessibility. More recent studies have shown that highly selected patients with AVMs can be treated with curative intent, leading to occlusion rates as high as 100% of such prospectively identified lesions with minimal morbidity. Advances in endovascular technology and techniques that support the efficacy and safety of curative embolization are discussed, as is the importance of superselective diagnostic angiography. Finally, the durability of curative embolization is analyzed. Overall, while still unproven, endovascular embolization has the potential to be a safe, effective, and durable curative treatment for select AVMs, broadening the armamentarium with which one can treat this disease.
Grace Y. Lai, Paul J. Devlin, Kartik Kesavabhotla, Jonathan D. Rich, Duc T. Pham, Matthew B. Potts, and Babak S. Jahromi
As the use of left ventricular assist devices (LVADs) has expanded, cerebrovascular complications have become an increasing source of morbidity and mortality in this population. Intracranial hemorrhage (ICH) in particular remains a devastating complication in patients who undergo LVAD placement with no defined management guidelines. The authors therefore reviewed surgical and anticoagulation management and outcomes of patients with LVADs who presented to their institution with ICH.
This retrospective cohort study assessed outcomes of patients who underwent LVAD placement at a single institution between 2007 and 2016 and in whom imaging demonstrated ICH.
During the study period, 281 patients had a HeartMate II or HeartWare LVAD placed. There were 37 episodes of ICH (recurrent in 3 cases). ICHs were categorized as intraparenchymal hemorrhage (IPH; n = 22, 59%), subdural hemorrhage (SDH; n = 6, 16%), and subarachnoid hemorrhage (SAH; n = 9, 24%). Neurosurgical intervention was deemed necessary in 27.3%, 66.7%, and 0% of patients with IPH, SDH, and SAH, respectively; overall survival > 30 days for each type of hemorrhage was 41%, 83%, and 89%, respectively. No patients had LVAD thrombus as a result of reversal of anticoagulation. Combined with prior reports, good outcomes are seen more often following surgery for SDH than for IPH (57% vs 7%, p = 0.004) in patients who underwent VAD placement.
Patients with IPH who undergo LVAD placement have poor outcomes regardless of anticoagulation reversal or neurosurgical intervention, whereas those with SDH may have good outcomes with medical and surgical intervention, and those with SAH appear to do well without anticoagulation reversal or surgery. When needed, anticoagulation reversal was not associated with an increase in LVAD thrombosis in this series.
Matthew B. Potts, Darryl Lau, Adib A. Abla, Helen Kim, William L. Young, and Michael T. Lawton
Resection is an appealing therapy for brain arteriovenous malformations (AVMs) because of its high cure rate, low complication rate, and immediacy, and has become the first-line therapy for many AVMs. To clarify safety, efficacy, and outcomes associated with AVM resection in the aftermath of A Randomized Trial of Unruptured Brain AVMs (ARUBA), the authors reviewed their experience with low-grade AVMs—the most favorable AVMs for surgery and the ones most likely to have been selected for treatment outside of ARUBA's randomization process.
A prospective AVM registry was searched to identify patients with Spetzler-Martin Grade I and II AVMs treated using resection during a 16-year period.
Of the 232 surgical patients included, 120 (52%) presented with hemorrhage, 33% had Spetzler-Martin Grade I, and 67% had Grade II AVMs. Overall, 99 patients (43%) underwent preoperative embolization, with unruptured AVMs embolized more often than ruptured AVMs. AVM resection was accomplished in all patients and confirmed angiographically in 218 patients (94%). There were no deaths among patients with unruptured AVMs. Good outcomes (modified Rankin Scale [mRS] score 0–1) were found in 78% of patients, with 97% improved or unchanged from their preoperative mRS scores. Patients with unruptured AVMs had better functional outcomes (91% good outcome vs 65% in the ruptured group, p = 0.0008), while relative outcomes were equivalent (98% improved/unchanged in patients with ruptured AVMs vs 96% in patients with unruptured AVMs).
Surgery should be regarded as the “gold standard” therapy for the majority of low-grade AVMs, utilizing conservative embolization as a preoperative adjunct. High surgical cure rates and excellent functional outcomes in patients with both ruptured and unruptured AVMs support a dominant surgical posture for low-grade AVMS, with radiosurgery reserved for risky AVMs in deep, inaccessible, and highly eloquent locations. Despite the technological advances in endovascular and radiosurgical therapy, surgery still offers the best cure rate, lowest risk profile, and greatest protection against hemorrhage for low-grade AVMs. ARUBA results are influenced by a low randomization rate, bias toward nonsurgical therapies, a shortage of surgical expertise, a lower rate of complete AVM obliteration, a higher rate of delayed hemorrhage, and short study duration. Another randomized trial is needed to reestablish the role of surgery in unruptured AVM management.