The impact of adding posterior instrumentation to transpsoas lateral fusion

J Neurosurg Spine 30:211–221, 2019

Transpsoas lateral interbody fusion is one of the lateral minimally invasive approaches for lumbar spine surgery. Most surgeons insert the interbody cage laterally and then insert pedicle or cortical screw and rod instrumentation posteriorly. However, standalone cages have also been used to avoid posterior instrumentation. To the best of the authors’ knowledge, the literature on comparison of the two approaches is sparse.

METHODS The authors performed a systematic review and meta-analysis of the available literature on transpsoas lateral interbody fusion by an electronic search of the PubMed, EMBASE, and Scopus databases using PRISMA guidelines. They compared patients undergoing transpsoas standalone fusion (TP) with those undergoing transpsoas fusion with posterior instrumentation (TPP).

RESULTS A total of 28 studies with 1462 patients were included. Three hundred and seventy-four patients underwent TPP, and 956 patients underwent TP. The mean patient age ranged from 45.7 to 68 years in the TP group, and 50 to 67.7 years in the TPP group. The incidence of reoperation was found to be higher for TP (0.08, 95% confidence interval [CI] 0.04–0.11) compared to TPP (0.03, 95% CI 0.01–0.06; p = 0.057). Similarly, the incidence of cage movement was found to be greater in TP (0.18, 95% CI 0.10–0.26) compared to TPP (0.03, 95% CI 0.00–0.05; p < 0.001). Oswestry Disability Index (ODI) and visual analog scale (VAS) scores and postoperative transient deficits were found to be comparable between the two groups.

CONCLUSIONS These results appear to suggest that addition of posterior instrumentation to transpsoas fusion is associated with decreased reoperations and cage movements. The results of previous systematic reviews and meta-analyses should be reevaluated in light of these results, which seem to suggest that higher reoperation and subsidence rates may be due to the use of the standalone technique.


Awake craniotomy versus craniotomy under general anesthesia without surgery adjuncts for supratentorial glioblastoma in eloquent areas

Acta Neurochirurgica (2019) 161:307–315

Awake craniotomy with electrocortical and subcortical mapping (AC) has become the mainstay of surgical treat- ment of supratentorial low-grade gliomas in eloquent areas, but not as much for glioblastomas.

Objective This retrospective controlled-matched study aims to determine whether AC increases gross total resections (GTR) and decreases neurological morbidity in glioblastoma patients as compared to resection under general anesthesia (GA, conventional). Methods Thirty-seven patients with glioblastoma undergoing AC were 1:3 controlled-matched with 111 patients undergoing GA for glioblastoma resection. The two groups were matched for age, gender, preoperative Karnofsky Performance Score (KPS), preoperative tumor volume, tumor location, and type of adjuvant treatment. Primary outcomes were extent of resection and the rate of postoperative complications. The secondary outcome was overall postoperative survival.

Results After matching, there were no significant differences in clinical variables between groups. Extent of resection was significantly higher in the AC group: mean extent of resection in the AC group was 94.89% (SD = 10.57) as compared to 70.30% (SD = 28.37) in the GA group (p = 0.0001). Furthermore, the mean rate of late minor postoperative complications in the AC group (0.03; SD = − 0.16) was significantly lower than in the GA group (0.15; SD = 0.39) (p = 0.05). No significant differences between groups were found for the other subgroups of postoperative complications. Moreover, overall postoperative survival did not differ between groups (p = 0.297).

Conclusion These findings suggest that resection of glioblastoma using AC is associated with significantly greater extent of resection and less late minor postoperative complications as compared with craniotomy under GA without the use of surgery adjuncts. However, due to certain limitations inherent to our study design (selection bias) and the absence of the use of surgery adjuncts in the GA group, we advocate for a prospective study to further build upon this evidence and study the use of AC in glioblastoma patients.

Degradation of Neuronal Encoding of Speech in the Subthalamic Nucleus in Parkinson’s Disease

Neurosurgery 84:378–387, 2019

Most of the patients with Parkinson’s disease suffer from speech disorders characterized mainly by dysarthria and hypophonia.

OBJECTIVE: To understand the deterioration of speech in the course of Parkinson’s disease.

METHODS: We intraoperatively recorded single neuron activity in the subthalamic nucleus of 18 neurosurgical patients with Parkinson’s disease undergoing implantation of deep brain stimulator while patients articulated 5 vowel sounds.

RESULTS: Here, we report that single subthalamic neurons encode individual vowel phonemes and employ 1 of 2 encoding schemes: broad or sharp tuning. Broadly tuned units respond to all examined phonemes, each with a different firing rate, whereas sharply tuned ones are specific to 1 to 2 phonemes. We then show that in comparison with patients without speech deficits, the spiking activity in patients with speech disorders was lower during speech production, overt or imagined, but not during perception. However, patients with speech disorders employed a larger percentage of the neurons for the aforementioned tasks. Whereas the lower firing rates affect mainly sharply tuned units, the extra units used a broad tuning encoding scheme.

CONCLUSION: Our findings suggest mechanisms of neuronal degradation due to Parkinsonian speech disorders and their possible compensation. As impairment in sharply tuned units may be compensated by broadly tuned ones, the proposed compensation model appears to be suboptimal, lending support to the persistence of speech disorders in the course of the disease.

Endoscopic endonasal surgery for epidermoid and dermoid cysts

J Neurosurg 130:368–378, 2019

Epidermoid and dermoid cysts may be found along the cranial base and are commonly resected via open transcranial approaches. The use of endoscopic endonasal approaches for resection of these tumors has been rarely reported.

METHODS The authors retrospectively reviewed the medical records of 21 patients who underwent endoscopic endonasal surgery for epidermoid and dermoid cyst resection at the University of Pittsburgh Medical Center between January 2005 and June 2014. Surgical outcomes and variables that might affect the extent of resection and complications were analyzed.

RESULTS Total resection (total removal of cyst contents and capsule) was achieved in 8 patients (38.1%), near-total resection (total removal of cyst contents, incomplete removal of cyst capsule) in 9 patients (42.9%), and subtotal resection (incomplete removal of cyst contents and capsule) in 4 patients (19%). Larger cyst volume (≥ 3 cm3) and intradural location (15 cysts) were significantly associated with nontotal resection (p = 0.008 and 0.0005, respectively). In the whole series, surgical complications were seen in 6 patients (28.6%). No complications were observed in patients with extradural cysts. Among the 15 patients with intradural cysts, the most common surgical complication was postoperative CSF leak (5 patients, 33.3%), followed by postoperative intracranial infection (4 patients, 26.7%). Larger cysts and postoperative CSF leak were associated with intracranial infection (p = 0.012 and 0.028, respectively). Subtotal resection was marginally associated with intracranial infection when compared with total resection (p = 0.091). All patients with neurological symptoms improved postoperatively with the exception of 1 patient with unchanged abducens nerve palsy.

CONCLUSIONS Endoscopic endonasal approaches may be effectively used for resection of epidermoid and dermoid cysts in carefully selected cases. These approaches are recommended for cases in which a total or near-total resection is possible in addition to a multilayer cranial base reconstruction with vascularized tissue to minimize the risk of intracranial infection.

Natural history of cavernous sinus meningiomas

J Neurosurg 130:435–442, 2019

Meningiomas confined to the cavernous sinus (MCSs) are benign tumors. Due to the high risk of severe complications, the intracavernous surgical procedure was abandoned in favor of radiotherapy. However, the choice of treatment remains complicated due to the fact that the natural history of this lesion has not yet been described.

METHODS The authors studied the natural history of this lesion using a prospective series of 53 consecutive patients suffering from MCSs. The median follow-up duration was 10.2 years (range 2–25 years), from 1990 to 2016.

RESULTS Patients ranged in age from 30 to 72 years (mean 53 years). The meningiomas were diagnosed by major symptoms (mainly oculomotor palsy and neuralgia experienced in 28 patients), minor symptoms (headache, intermittent diplopia in 15 patients), or incidental findings (10 patients). Simple symptomatic treatment (short courses of cortico- steroids and carbamazepine) allowed patients to become asymptomatic in 19 (67.9%) of 28 cases experiencing major symptoms, and for 12 (80%) of 15 patients with initial minor symptoms (p < 0.0001). All patients with incidental findings remained asymptomatic. Forty four (83%) of 53 MCSs did not show any significant growth and 42 (80%) of 53 patients were not symptomatic at the end of follow-up (p < 0.001). The radiographic progression-free survival rates (± SD) at 5, 10, and 20 years were 90% ± 4.2%, 82% ± 5.7%, and 70% ± 10.2%, respectively. Five patients (9.4%) with no evidence of any effect of the initial medical treatment desired additional conventional radiation therapy.

CONCLUSIONS Because of the capricious, unpredictable, and slow growth of MCSs, together with high growth variability from one patient to the next, the symptomatic medical treatment of these tumors is a highly effective method. This series shows that these lesions are naturally, clinically, and radiologically indolent.

Stereotactic Radiosurgery for Trigeminal Neuralgia in Patients With Multiple Sclerosis: A Multicenter Study

Neurosurgery 84:499505, 2019

Facial pain response (PR) to various surgical interventions in patients with multiple sclerosis (MS)-related trigeminal neuralgia (TN) is much less optimal. No large patient series regarding stereotactic radiosurgery (SRS) has been published.

OBJECTIVE: To evaluate the clinical outcomes of MS-related TN treated with SRS.

METHODS: This is a retrospective cohort study. A total of 263 patients contributed by 9 member tertiary referral Gamma Knife centers (2 in Canada and 7 in USA) of the Interna- tional Gamma Knife Research Consortium (IGKRF) constituted this study.

RESULTS: The median latency period of PR after SRS was 1 mo. Reasonable pain control (Barrow Neurological Institute [BNI] Pain Scores I-IIIb) was achieved in 232 patients (88.2%). The median maintenance period from SRS was 14.1 months (range, 10 days to 10 years). The actuarial reasonable pain control maintenance rates at 1 yr, 2 yr, and 4 yr were 54%, 35%, and 24%, respectively. There was a correlation between the status of achieving BNI-I and the maintenance of facial pain recurrence-free rate. The median recurrence-free rate was 36 mo and 12.2 mo in patients achieving BNI-I and BNI > I, respectively (P = .046). Among 210 patients with known status of post-SRS complications, the new-onset of facial numbness (BNI-I or II) after SRS occurred in 21 patients (10%).

CONCLUSION: In this largest series SRS offers a reasonable benefit to risk profile for patients who have exhausted medical management. More favorable initial response to SRS may predict a long-lasting pain control.

Origin of Syrinx Fluid in Syringomyelia: A Physiological Study

Neurosurgery 84:457–468, 2019

The origin of syrinx fluid is controversial.

OBJECTIVE: To elucidate themechanisms of syringomyelia associated with cerebrospinal fluid pathway obstruction and with intramedullary tumors, contrast transport from the spinal subarachnoid space (SAS) to syrinx was evaluated in syringomyelia patients.

METHODS: We prospectively studied patients with syringomyelia: 22 with Chiari I malformation and 16 with SAS obstruction-related syringomyelia before and 1 wk after surgery, and 9 with tumor-related syringomyelia before surgery only. Computed tomographymyelography quantified dye transport into the syrinx before and 0.5, 2, 4, 6, 8, 10, and 22 h after contrast injection by measuring contrast density in Hounsfield units (HU).

RESULTS: Before surgery, more contrast passed into the syrinx in Chiari I malformation related syringomyelia and spinal obstruction-related syringomyelia than in tumor-related syringomyelia, as measured by (1) maximum syrinx HU, (2) area under the syrinx concentration-time curve (HU AUC), (3) ratio of syrinx HU to subarachnoid cerebrospinal fluid (CSF; SAS) HU, and (4) AUC syrinx/AUC SAS. More contrast (AUC) accumulated in the syrinx and subarachnoid space before than after surgery.

CONCLUSION: Transparenchymal bulk flow of CSF from the subarachnoid space to syrinx occurs in Chiari I malformation-related syringomyelia and spinal obstruction-related syringomyelia. Before surgery, more subarachnoid contrast entered syringes associated with CSF pathway obstruction than with tumor, consistent with syrinx fluid originating from the subarachnoid space in Chiari I malformation and spinal obstruction-related syringomyelia and not from the subarachnoid space in tumor-related syringomyelia. Decompressive surgery opened subarachnoid CSF pathways and reduced contrast entry into syringes associated with CSF pathway obstruction.

Artificial disc replacement versus fusion in patients with cervical degenerative disc disease with radiculopathy: 5-year outcomes from the National Swedish Spine Register

J Neurosurg Spine 30:159–167, 2019

The long-term efficacy of artificial disc replacement (ADR) surgery compared with fusion after decompression for the treatment of cervical degenerative disc disease and radiculopathy has not previously been investigated in a population-based setting.

METHODS All patients with cervical degenerative disc disease and radiculopathy who were in the national Swedish Spine Registry (Swespine) beginning in January 1, 2006, were eligible for the study. Follow-up information was obtained up to November 15, 2017. The authors compared, using propensity score matching, patients treated with anterior decompression and insertion of an ADR with patients who underwent anterior decompression combined with fusion surgery.
The primary outcome was the Neck Disability Index (NDI), a patient-reported function score ranging from 0% to 100%, with higher scores indicating greater disability and a minimum clinically important difference of > 15%.

RESULTS A total of 3998 patients (2018:1980 women/men) met the inclusion criteria, of whom 204 had undergone arthroplasty and 3794 had undergone fusion. After propensity score matching, 185 patients with a mean age of 49.7 years remained in each group. Scores on the NDI were approximately halved in both groups after 5 years, but without a significant mean difference in NDI (3.0%; 95% CI -8.4 to 2.4; p = 0.28) between the groups. There were no differences between the groups in EuroQol–5 Dimensions or in pain scores for the neck and arm.

CONCLUSIONS In patients with cervical degenerative disc disease and radiculopathy, decompression plus ADR surgery did not result in a clinically important difference in outcomes after 5 years, compared with decompression and fusion surgery.

Detection rates and sites of unruptured intracranial aneurysms according to sex and age: an analysis of MR angiography–based brain examinations of 4070 healthy Japanese adults

J Neurosurg 130:573–578, 2019

The purpose of this study was to evaluate the detection rate and occurrence site according to patient sex and age of unruptured intracranial aneurysms detected through MRI and MR angiography (MRA).

METHODS A total of 4070 healthy adults 22 years or older (mean age [± SD] 50.6 ± 11.0 years; 41.9% women) who underwent a brain examination known as “Brain Dock” in the central Tokyo area between April 2014 and March 2015 were checked for unruptured saccular aneurysm using 3-T MRI/MRA. The following types of cases were excluded: 1) protrusions with a maximum diameter < 2 mm at locations other than arterial bifurcations, 2) conical protrusions at arterial bifurcations with a diameter < 3 mm, and 3) cases of suspected aneurysms with unclear imaging of the involved artery. When an aneurysm was definitively diagnosed, the case was included in the aneurysm group. The authors also investigated the relationship between aneurysm occurrence and risk factors (age, sex, smoking history, hypertension, diabetes, and hyperlipidemia).

RESULTS One hundred eighty-eight aneurysms were identified in 176 individuals (detection rate 4.32%), with the detection rate for women being significantly higher (6.2% vs 3.0%, p < 0.001). The average age in the aneurysm group was significantly higher than in the patients in whom aneurysms were not detected (53.0 ± 11.1 vs 50.5 ± 11.0 years). The detection rate tended to increase with age. The detection rates were 3.6% for people in their 30s, 3.5% for those in their 40s, 4.1% for those in their 50s, 6.9% for those in their 60s, and 6.8% for those in their 70s. Excluding persons in their 20s and 80s—age groups in which no aneurysms were discovered—the detection rate in women was higher in all age ranges. Of the individuals with aneurysms, 12 (6.81%) had multiple cerebral aneurysms; no sex difference was observed with respect to the prevalence of multiple aneurysms. Regarding aneurysm size, 2.0–2.9 mm was the most common size range, with 87 occurrences (46.3%), followed by 3.0–3.9 mm (67 [35.6%]) and 4.0–4.9 mm (20 [10.6%]). The largest aneurysm was 13 mm. Regarding location, the internal carotid artery (ICA) was the most common aneurysm site, with 148 (78.7%) occurrences. Within the ICA, C1 was the site of 46 aneurysms (24.5%); C2, 57 (30.3%); and C3, 29 (15.4%). The aneurysm detection rates for C2, C3, and C4 were 2.23%, 1.23%, and 0.64%, respectively, for women and 0.68%, 0.34%, and 0.21%, respectively, for men; ICA aneurysms were significantly more common in women than in men (5.27% vs 2.20%, p < 0.001). Multivariate logistic regression analysis revealed that age (p < 0.001, OR 1.03, 95% CI 1.01–1.04), female sex (p < 0.001, OR 2.28, 95% CI 1.64–3.16), and smoking history (p = 0.011, OR 1.52, 95% CI 1.10–2.11) were significant risk factors for aneurysm occurrence

CONCLUSIONS In this study, both female sex and older age were independently associated with an increased aneurysm detection rate. Aneurysms were most common in the ICA, and the frequency of aneurysms in ICA sites was markedly higher in women.

Internal maxillary artery bypass for the treatment of complex middle cerebral artery aneurysms

Neurosurg Focus 46 (2):E10, 2019

The rapid innovation of the endovascular armamentarium results in a decreased number of indications for a classic surgical approach. However, a middle cerebral artery (MCA) aneurysm remains the best example of one for which results have favored microsurgery over endovascular intervention. In this study, the authors aimed to evaluate the experience and efficacy regarding surgical outcomes after applying internal maxillary artery (IMA) bypass for complex MCA aneurysms (CMCAAs).
METHODS All IMA bypasses performed between January 2010 and July 2018 in a single-center, single-surgeon practice were screened.
RESULTS In total, 12 patients (9 males, 3 females) with CMCAAs managed by high-flow IMA bypass were identified. The mean size of CMCAAs was 23.7 mm (range 10–37 mm), and the patients had a mean age of 31.7 years (range 14–56 years). The aneurysms were proximally occluded in 8 cases, completely trapped in 3 cases, and completely resected in 1 case. The radial artery was used as the graft vessel in all cases. At discharge, the graft patency rate was 83.3% (n = 10), and all aneurysms were completely eliminated (83.3%, n = 10) or greatly diminished (16.7%, n = 2) from the circulation. Postoperative ischemia was detected in 2 patients as a result of graft occlusion, and 1 patient presenting with subarachnoid hemorrhage achieved improved modified Rankin Scale scores compared to the preoperative status but retained some neurological deficits. Therefore, neurological assessment at discharge showed that 9 of the 12 patients experienced unremarkable outcomes. The mean interval time from bypass to angiographic and clinical follow-up was 28.7 months (range 2–74 months) and 53.1 months (range 19–82 months), respectively. Although 2 grafts remained occluded, all aneurysms were isolated from the circulation, and no patient had an unfavorable outcome.
CONCLUSIONS The satisfactory result in the present study demonstrated that IMA bypass is a promising method for the treatment of CMCAAs and should be maintained in the neurosurgical armamentarium. However, cases with intraoperative radical resection or inappropriate bypass recipient selection such as aneurysmal wall should be meticulously chosen with respect to the subtype of MCA aneurysm.

Neck Remnants and the Risk of Aneurysm Rupture After Endovascular TreatmentWith Coiling or Stent-Assisted Coiling

Neurosurgery 84:421–427, 2019

Neck remnants are not uncommon after endovascular treatment of cerebral aneurysms. Critics of endovascular treatments for cerebral aneurysms cite neck remnants as evidence in favor of microsurgical clipping. However, studies have failed to evaluate the true clinical significance of aneurysm neck remnants following endovascular therapies.

OBJECTIVE: To assess the clinical significance of residual aneurysm necks and to determine the rate of subsequent rupture following coiling or stent-assisted coiling of cerebral aneurysms.

METHODS: We retrospectively reviewed the records of 1292 aneurysm cases that underwent endovascular treatment at 4 institutions. Aneurysms treated by primary coiling or stent-assisted coiling were included in the study; those treated by flow diversion were excluded Aneurysms with residual filling (i.e., Raymond–Roy Occlusion Classification II, neck remnant; or III, residual aneurysm filling) were assessed for their risk of subsequent rupture.

RESULTS: A total of 626 aneurysms were identified as having residual filling immediately posttreatment. Of these, 13 aneurysms (2.1%) ruptured during the follow-up period (mean 7.3 mo; range 1-84 mo). Eleven of the 13 (84.6%) were ruptured at presentation. Rupture at presentation, the size of the aneurysm, and the increasing age of the patient were predictive of posttreatment rupture.

CONCLUSION: We found that unruptured aneurysms with residual necks following endovascular treatment posed a very low risk of rupture (0.6%). However, patients presenting with ruptured aneurysms had a higher risk of rerupture from a neck remnant (3.4%). These results highlight the importance of achieving complete angiographic occlusion of ruptured aneurysms.

Symptomatic Adjacent Level Disease Requiring Surgery: Analysis of 10-Year Results From a Prospective, Randomized, Clinical Trial Comparing Cervical Disc Arthroplasty to Anterior Cervical Fusion

Neurosurgery 84:347–354, 2019

Ten-year follow-up data from the US Food and Drug Administration investigational device exemption trial comparing BRYAN  Cervical Disc (Medtronic, Dublin, Ireland) arthroplasty to anterior cervical discectomy and fusion (ACDF) demonstrated that disc arthroplasty maintained range of motion and improvements in overall success and neck disability.

OBJECTIVE: To compare the 10-yr rates of symptomatic adjacent level disease requiring surgery (SALDRS).

METHODS: Prospective randomized trial data were analyzed comparing BRYANR  Cervical Disc arthroplasty to ACDF for single-level cervical disc disease with concordant radiculopathy or myelopathy with clinicoradiographic analysis at 10 yr. Secondarily, 84-mo data were pooled with PRESTIGE   Cervical Disc arthroplasty (Medtronic) study data to provide overall rates of SALDRS.

RESULTS: Significantly greater overall success was maintained at every postoperative interval with an overall success rate of 81.3% with BRYAN  disc and 66.3% with ACDF (P = .005) without loss of motion preservation (8.69◦ vs 0.60◦). Reoperation at adjacent levels up to the 120-mo visit was 9.7% in the arthroplasty group and 15.8% in the ACDF group (P = .146). The combined data from BRYAN and Prestige ST demonstrate that BRYAN  and Prestige disc groups had a lower rate of second surgeries at the adjacent levels, up to the 84-mo visit, compared to the combined ACDF groups (6.9% vs 11.7%; P = .023).

CONCLUSION: Compared with ACDF, fewer patients with the BRYAN  disc required surgery for symptomatic adjacent level degeneration, but this did not achieve statistical significance. Analysis of combined study data using Bryan and Prestige discs shows significant differences in SADLRS as early as 7 yr.


Effect of Bilateral Anterior Cingulotomy on Chronic Neuropathic Pain with Severe Depression

World Neurosurg. (2019) 121:196-200.

The presence of neuropathic pain can severely impinge on emotional regulation and activities of daily living including social activities, resulting in diminished life satisfaction. Unfortunately, the majority of patients with neuropathic pain do not experience an amelioration of symptoms from conventional therapies, even when multimodal therapies are used. Chronic refractory neuropathic pain is usually accompanied by severe depression that is prone to incur suicidal events; thus clinical management of chronic neuropathic pain and depression presents a serious challenge for clinicians and patients.

CASE DESCRIPTION: Two patients presented at our institution with neuropathic pain and severe depression. The patients had different pain symptoms emerging a few months after central or peripheral nervous system impairment. These symptoms were associated with the development of severe depression, social isolation, and a gradual inability to perform daily activities. Both patients were referred to our treatment center for bilateral anterior cingulotomy. After surgery, both patients showed significant progressive improvements in perceived pain, mental health status, and daily functioning. –

CONCLUSIONS: Bilateral anterior cingulotomy may serve as an alternative treatment for medically refractory neuropathic pain, especially for patients who also experience depression

Pterional versus superciliary keyhole approach

J Neurosurg 130:220–226, 2019

The objective of this study was to evaluate and compare the level of patient satisfaction and approachrelated patient complaints between a superciliary keyhole approach and a pterional approach.

METHODS Patients who underwent an ipsilateral superciliary keyhole approach and a contralateral pterional approach for bilateral intracranial aneurysms during an 11-year period were contacted and asked to complete a patient satisfaction questionnaire. The questionnaire covered 5 complaint areas related to the surgical approaches: craniotomy-related pain, sensory symptoms in the head, cosmetic complaints, palpable cranial irregularities, and limited mouth opening. The patients were asked to rate the 5 complaint areas on a scale from 0 (asymptomatic or very pleasant) to 4 (severely symptomatic or very unpleasant). Finally, the patients were asked to rate the level of overall satisfaction related to each surgical procedure on a visual analog scale (VAS) from 0 (most unsatisfactory) to 100 (most satisfactory).

RESULTS A total of 21 patients completed the patient satisfaction questionnaire during a follow-up clinic visit. For the superciliary procedures, no craniotomy-related pain, palpable irregularities, or limited mouth opening was reported, and only minor sensory symptoms (numbness in the forehead) and cosmetic complaints (short linear operative scar) were reported (score = 1) by 1 (4.8%) and 3 patients (14.3%), respectively. Compared with the pterional approach, the superciliary approach showed better outcomes regarding the incidence of craniotomy-related pain, cosmetic complaints, and palpable irregularities, with a significant between-approach difference (p < 0.05). Furthermore, the VAS score for patient satisfaction was significantly higher for the superciliary approach (mean 95.2 ± 6.0 [SD], range 80–100) than for the pterional approach (mean 71.4 ± 10.6, range 50–90). Moreover, for the pterional approach, a multiple linear regression analysis indicated that the crucial factors decreasing the level of patient satisfaction were cosmetic complaints, craniotomy- related pain, and sensory symptoms, in order of importance (p < 0.05).

CONCLUSIONS In successful cases in which the primary surgical goal of complete aneurysm clipping without postoperative complications is achieved, a superciliary keyhole approach provides a much higher level of patient satisfaction than a pterional approach, despite a facial wound. For a pterional approach, the patient satisfaction level is affected by the cosmetic results, craniotomy-related pain, and numbness behind the hairline, in order of importance.


Stereotactic Radiosurgery for Intracranial Ependymomas: An International Multicenter Study

Neurosurgery 84:227–234, 2019

Stereotactic radiosurgery (SRS) is a potentially important option for intracranial ependymoma patients.

OBJECTIVE: To analyze the outcomes of intracranial ependymoma patients who underwent SRS as a part of multimodality management.

METHODS: Seven centers participating in the International Gamma Knife Research Foundation identified 89 intracranial ependymoma patients who underwent SRS (113 tumors). The median patient age was 16.3 yr (2.9-80). All patients underwent previous surgical resection and radiation therapy (RT) of their ependymomas and 40 underwent previous chemotherapy. Grade 2 ependymomas were present in 42 patients (52 tumors) and grade 3 ependymomas in 48 patients (61 tumors). The median tumor volume was 2.2 cc (0.03-36.8) and the median margin dose was 15 Gy (9-24).

RESULTS: Forty-seven (53%) patients were alive and 42 (47%) patients died at the last follow-up. The overall survival after SRSwas 86% at 1 yr, 50% at 3 yr, and 44% at 5 yr. Smaller total tumor volume was associated with longer overall survival (P = .006). Twenty-two patients (grade 2: n = 9, grade 3: n = 13) developed additional recurrent ependymomas in the craniospinal axis. The progression-free survival after SRSwas 71%at 1 yr, 56% at 3 yr, and 48% at 5 yr. Adult age, female sex, and smaller tumor volume indicated significantly better progression-free survival. Symptomatic adverse radiation effects were seen in 7 patients (8%).

CONCLUSION: SRS provides another management option for residual or recurrent progressive intracranial ependymoma patients who have failed initial surgery and RT.

Anatomic Characteristics of Intrapetrous Carotid Artery: A 3-Dimensional Segmentation Study on Head Computed Tomography Scan

World Neurosurg. (2019) 121:e419-e425

The intrapetrous carotid artery (IPCA) is one of the most unexplored anatomic regions, and its 3-dimensional reconstruction in living subjects is still missing. This study aims to describe the IPCA on 3D models extracted from head computed tomography (CT) scans.

METHODS: The intrapetrous carotid artery was manually segmented on head CT scans of 100 healthy patients free from vascular and neurologic pathologies (50 men and 50 women; age range, 18e91 years). Angles of the posterior and anterior genu, diameter and length of the horizontal portion, and volume of the entire canal were calculated through 3D analysis software. Statistically significant differences according to sex and side were assessed through 2-way analysis of variance (P < 0.05). Correlation of each measurement with age was calculated as well.

RESULTS: On average, the angles of the posterior and anterior genu were 120.1±2.4 and 118.0±10.0 in men and 119.5±9.2 and 117.6±10.3 in women, respectively, without statistically significant differences according to sex or side (P > 0.05). The average length and diameter of the horizontal part were, respectively, 25.5±2.9 and 5.8±0.8 mm in men and 24.0±2.3 and 5.3±0.8 mm in women. The volume of the IPCA was 0.941±0.215 cm3 in men and 0.752±0.159 cm3 in women. The length and diameter of the horizontal portion and the volume of the IPCA showed statistically significant differences according to sex (P < 0.05). No correlation with age was found.

CONCLUSIONS: This study provides data concerning not only linear and angular measurements, but also volumes of the IPCA, which are useful in planning surgical interventions of the cranial base.

Functional Balance Testing in Cervical Spondylotic Myelopathy Patients

Spine 2019;44:103–109

Study Design. A prospective cohort study.

Objective. The aim of this study was to quantify the amount of sway associated with maintaining a balanced posture in a group of untreated cervical spondylotic myelopathy (CSM) patients.

Summary of Background Data. Balance is defined as the ability of the human body to maintain its center of mass (COM) within the base of support with minimal postural sway. Sway is the movement of the COM in the horizontal plane when a person is standing in a static position. CSM patients have impaired body balance and proprioceptive loss.

Methods. Thirty-two CSM patients performed a series of functional balance tests a week before surgery. Sixteen healthy controls (HCs) performed a similar balance test. Patients are instructed to stand erect with feet together and eyes opened in their self-perceived balanced and natural position for a full minute. All test subjects were fitted to a full-body reflective markers set and surface electromyography (EMG).

Results. CSM patients had more COM sway in the anteriorposterior (CSM: 2.87cm vs. C: 0.74 cm; P¼0.023), right-left (CSM: 5.16cm vs. C: 2.51 cm; P¼0.003) directions as well as head sway (anterior-posterior – CSM: 2.17cm vs. C: 0.82 cm; P ¼0.010 and right-left – CSM: 3.66 cm vs. C: 1.69cm; P¼0.044), more COM (CSM: 44.72 cm vs. HC: 19.26 cm, p¼0.001), and head (Pre: 37.87cm vs. C: 19.93 cm, P¼0.001) total sway in comparison to controls. CSM patients utilized significantly more muscle activity to maintain static standing, evidenced by the increased trunk and lower extremity muscle activity (multifidus, erector spinae, rectus femoris, and tibialis anterior, P<0.050) during 1-minute standing.

Conclusion. In symptomatic CSM patients, COM and head total sway were significantly greater than controls. Individuals with CSM exhibit more trunk and lower extremity muscle activity, and thus expend more neuromuscular energy to maintain a balanced, static standing posture. This study is the first effort to evaluate global balance as a dynamic process in this patient population.

Level of Evidence: 3

Anterior clinoidectomy using an extradural and intradural 2-step hybrid technique

J Neurosurg 130:238–247, 2019

Anterior clinoidectomy is a difficult yet essential technique in skull base surgery. Two main techniques (extradural and intradural) with multiple modifications have been proposed to increase efficiency and avoid complications.

In this study, the authors sought to develop a hybrid technique based on localization of the optic strut (OS) to combine the advantages and avoid the disadvantages of both techniques. Ten cadaveric specimens were prepared for surgical simulation. After a standard pterional craniotomy, the anterior clinoid process (ACP) was resected in 2 steps. The segment anterior to the OS was resected extradurally, while the segment posterior to the OS was resected intradurally. The proposed technique was performed in 6 clinical cases to evaluate its safety and efficiency.

Anterior clinoidectomy was successfully performed in all cadaveric specimens and all 6 patients by using the proposed technique. The extradural phase enabled early decompression of the optic nerve while avoiding the adjacent internal carotid artery. The OS was drilled intradurally under direct visualization of the adjacent neurovascular structures. The described landmarks were easily identifiable and applicable in the surgically treated patients. No operative complication was encountered.

A proposed 2-step hybrid technique combines the advantages of the extradural and intradural techniques while avoiding their disadvantages. This technique allows reduced intradural drilling and subarachnoid bone dust deposition. Moreover, the most critical part of the clinoidectomy—that is, drilling of the OS and removal of the body of the ACP—is left for the intradural phase, when critical neurovascular structures can be directly viewed.


Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion

J Neurosurg Spine 30:46–51, 2019

Common interbody graft options for anterior cervical discectomy and fusion (ACDF) include structural allograft and polyetheretherketone (PEEK). PEEK has gained popularity due to its radiolucency and its elastic modulus, which is similar to that of bone. The authors sought to compare the rates of pseudarthrosis, a lack of solid bone growth across the disc space, and the need for revision surgery with the use of grafts made of allogenic bone versus PEEK.

METHODS The authors retrospectively reviewed 127 cases in which patients had undergone a 1-level ACDF followed by at least 1 year of radiographic follow-up. Data on age, sex, body mass index, tobacco use, pseudarthrosis, and the reoperation rate for pseudarthrosis were collected. These data were analyzed by performing a Pearson’s chi-square test.

RESULTS Of 127 patients, 56 had received PEEK implants and 71 had received allografts. Forty-six of the PEEK implants (82%) were stand-alone devices. There were no significant differences between the 2 treatment groups with respect to patient age, sex, or body mass index. Twenty-nine (52%) of 56 patients with PEEK implants demonstrated radiographic evidence of pseudarthrosis, compared to 7 (10%) of 71 patients with structural allografts (p < 0.001, OR 9.82; 95% CI 3.836–25.139). Seven patients with PEEK implants required reoperation for pseudarthrosis, compared to 1 patient with an allograft (p = 0.01, OR 10.00; 95% CI 1.192–83.884). There was no significant difference in tobacco use between the PEEK and allograft groups (p = 0.586).

CONCLUSIONS The results of this study demonstrate that the use of PEEK devices in 1-level ACDF is associated with a significantly higher rate of radiographically demonstrated pseudarthrosis and need for revision surgery compared with the use of allografts. Surgeons should be aware of this when deciding on interbody graft options, and reimbursement policies should reflect these discrepancies.