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BACKGROUND: Idiopathic spinal cord herniations (ISCH) are rare defects of the ventromedial or mediolateral dura mater with herniation of the spinal cord through the defect with approximately 350 described cases worldwide. Patients usually become symptomatic with motor or sensory neurological deficits and gait disturbances. OBJECTIVE: To describe characteristic symptoms and clinical findings and to evaluate the postoperative course and outcomes of ISCH. METHODS: We present a single-center data analysis of a case series of 11 consecutive patients who were diagnosed with ISCH and underwent surgery in our department between 2009 and 2021. RESULTS: All herniations were located in the thoracic spine between T2 and T9. In most cases, gait ataxia and dysesthesia led to further workup and subsequently to the diagnosis of ISCH. A “far-enough” posterior-lateral surgical approach, hemilaminectomy or laminectomy with a transdural approach, was performed under intraoperative neurophysiological monitoring which was followed by adhesiolysis, repositioning of the spinal cord and sealing using a dura patch. After surgery, clinical symptoms improved in 9 of 11 patients (81.8%), while only 1 patient experienced deterioration of symptoms (9.1%) and 1 patient remained equal (9.1%). The median preoperative McCormick grade was 3 (±0.70), while the median postoperative grade was 2 (±0.98) (P = .0047). CONCLUSION: In our case series of ISCH, we found that in most patients, neurological deficits improved postoperatively. This indicates that surgery in ISCH should not be delayed in symptomatic patients.

Background Surgery for intra-/extraforaminal disk herniations (IEDH) is technically demanding due to the hidden location of the compressed nerve root section. Ipsilateral approaches (medial and lateral) are accompanied by extended resection of the facet joint and inadequate visualization of the pathology, especially at the L5–S1 level. Methods We describe a microsurgical interlaminar contralateral approach (MICA) suitable for IEDH at the lumbosacral junction that can also be used at L4–L5 and L3–L4. Conclusion The MICA provides access and sufficient intraforaminal visualization for IEDH in the lumbosacral region without resection of stability-relevant structures or manipulation of the nerve root ganglion.

OBJECTIVE With global aging, elective craniotomies are increasingly being performed in elderly patients. There is a paucity of prospective studies evaluating the impact of these procedures on the geriatric population. The goal of this study was to assess the safety of elective craniotomies for elderly patients in modern neurosurgery. METHODS For this cohort study, adult patients, who underwent elective craniotomies between November 1, 2011, and October 31, 2018, were allocated to 3 age groups (group 1, < 65 years [n = 1008], group 2, ≥ 65 to < 75 [n = 315], and group 3, ≥ 75 [n = 129]). Primary outcome was the 30-day mortality after craniotomy. Secondary outcomes included rate of delayed extubation (> 1 hour), need for emergency head CT scan and reoperation within 48 hours after surgery, length of postoperative intensive or intermediate care unit stay, hospital length of stay (LOS), and rate of discharge to home. Adjustment for American Society of Anesthesiologists Physical Status (ASA PS) class, estimated blood loss, and duration of surgery were analyzed as a comparison using multiple logistic regression. For significant differences a post hoc analysis was performed. RESULTS In total, 1452 patients (mean age 55.4 ± 14.7 years) were included. The overall mortality rate was 0.55% (n = 8), with no significant differences between groups (group 1: 0.5% [95% binominal CI 0.2%, 1.2%]; group 2: 0.3% [95% binominal CI 0.0%, 1.7%]; group 3: 1.6% [95% binominal CI 0.2%, 5.5%]). Deceased patients had a significantly higher ASA PS class (2.88 ± 0.35 vs 2.42 ± 0.62; difference 0.46 [95% CI 0.03, 0.89]; p = 0.036) and increased estimated blood loss (1444 ± 1973 ml vs 436 ± 545 ml [95% CI 618, 1398]; p CONCLUSIONS Mortality following elective craniotomy was low in all age groups. Today, elective craniotomy for well-selected patients is safe, and for elderly patients, too. Elderly patients are more dependent on discharge to other hospitals and postacute care facilities after elective craniotomy. Clinical trial registration no.: NCT01987648 (clinicaltrials.gov).

ZusammenfassungBei der idiopathischen ventralen Rückenmarksherniation handelt es sich um einen sehr seltenen Defekt der thorakalen ventralen Dura, am häufigsten zwischen BWK 2 und BWK 8, mit konsekutivem Prolaps des Myelons in diesen Duradefekt hinein. Klinisch führt dies oft nach jahrelanger Anamnese zu einer progredienten, mehr oder weniger stark ausgeprägten Myelopathie, z. B. einem Brown-Séquard Syndrom oder einer Paraparese. Die Ursache des Duradefekts und der Mechanismus der Herniation sind nicht geklärt. Diskutiert werden Bandscheibenpathologien wie verkalkte Mikrosporne, Trauma, Entzündung, eine Bindegewebsschwäche und angeborene Dura-Duplikaturen. Die wichtigsten Differentialdiagnosen sind arachnoidale Zysten und arachnoidale Netze (arachnoidal web), die das Myelon bei jedoch intakter Dura nach ventral verlagern, Tumore sowie ischämische und traumatische Myelomalazien. Trotz exzellenter Bildgebung gelingt manchmal die sichere Diagnose einer Myelonhernie samt Duradefekt letztendlich erst intraoperativ. Die operative Versorgung ist, einschließlich auch der nur leicht symptomatischen Patienten, die Therapie der Wahl und stellt eine neurochirurgische Herausforderung dar. Ziel ist das Lösen des Rückenmarks mit, je nach Größe und Lage, entweder Verschluss, Augmentation oder Erweiterung des Duradefekts. Das Risiko für postoperative Defizite beträgt 5–12%. Von einem Behandlungserfolg wird meist bei einem Stopp der klinischen Progression ausgegangen, wobei bis zu 3/4 der Patienten eine Chance auf postoperative Besserung haben. Die operative Behandlung sollte mit intraoperativem Neuromonitoring (SSEP, MEP, D-Welle) in Zentren mit entsprechender Erfahrung erfolgen. Patienten, bei denen noch keine Operationsindikation gestellt wurde, sollten engmaschig angebunden werden, da der natürliche Krankheitsverlauf der idiopathischen ventralen Rückenmarksherniation meist progredient ist.

BACKGROUND AND PURPOSE: CSF loss in spontaneous intracranial hypotension disrupts a well-regulated equilibrium. We aimed to evaluate the volume shift between intracranial compartments in patients with spontaneous intracranial hypotension before and after surgical closure of the underlying spinal dural breach. MATERIALS AND METHODS: In total, 19 patients with spontaneous intracranial hypotension with a proved spinal CSF leak investigated at our institution between July 2014 and March 2017 (mean age, 41.8 years; 13 women) were included. Brain MR imaging–based volumetry at baseline and after surgery was performed with FreeSurfer. In addition, the spontaneous intracranial hypotension score, ranging from 0 to 9, with 0 indicating very low and 9 very high probability of spinal CSF loss, was calculated. RESULTS: Total mean ventricular CSF volume significantly increased from baseline (15.3 mL) to posttreatment MR imaging (18.0 mL), resulting in a mean absolute and relative difference, +2.7 mL and +18.8% (95% CI, +1.2 to +3.9 mL; P

ObjectiveTo assess the pathophysiologic changes in patients with spontaneous intracranial hypotension (SIH) based on measures of CSF dynamics, and on the duration of symptoms, in a retrospective case-controlled study.MethodsWe included consecutive patients investigated for SIH at our department from January 2012 to February 2018. CSF leak was considered confirmed if extrathecal contrast spillage was seen on imaging (CT or MRI) after intrathecal contrast application, or dural breach was detected by direct intraoperative visualization. We divided patients with a confirmed CSF leak into 3 groups depending on the symptom duration, as follows: ≤10, 11–52, and >52 weeks. Clinical characteristics and measures of CSF fluid dynamics obtained by computerized lumbar infusion testing were analyzed over time and compared with a reference population.ResultsAmong the 137 patients included, 69 had a confirmed CSF leak. Whereas 93.1% with 10 weeks of symptoms did (p = 0.004). Analysis of infusion tests revealed differences between groups with different symptom duration for CSF outflow resistance (p < 0.001), lumbar baseline pressure (p = 0.013), lumbar plateau pressure (p < 0.001), baseline pressure amplitude (p = 0.021), plateau pressure amplitude (p = 0.001), pressure–volume index (p = 0.001), elastance (p < 0.001), and CSF production rate (p = 0.001). Compared to the reference population, only patients with acute symptoms showed a significantly altered CSF dynamics profile.ConclusionA CSF leak dramatically alters CSF dynamics acutely, but the pattern changes over time. There is an association between the clinical presentation and changes in CSF dynamics.

Background Spinal imaging is essential to identify and localize cerebrospinal fluid (CSF) leaks in spontaneous intracranial hypotension (SIH) patients when targeted treatment is necessary. Purpose Provide an in-depth presentation of the conventional dynamic myelography (CDM) technique for localizing spinal CSF leaks in SIH patients. Material and Methods Consecutive SIH patients with a CSF leak confirmed on CDM and postmyelography computed tomography (CT) investigated at our institution between 2013 and 2019 were retrospectively analyzed. Intraoperative reports were reviewed to confirm the accuracy of CDM. Results In total, 62 patients (mean age 45 years) were included; 48 with a ventral dural tear, 12 with a meningeal diverticulum, and in 2 patients positive for spinal longitudinal extradural CSF collection the site remained unclear. The leak was identified during the first and the second CDM in 43 and 17 patients, respectively. The use of CDM correctly identified the site of the CSF leak in all but one patient undergoing surgical closure (45/46, 98%). The mean fluoroscopy time was 7.8 min (range 1.8–14.4 min) with a radiation dose for a single examination of 310 mGy (range 28–1237 mGy). Conclusion The CDM procedure has a high accuracy for spinal CSF leak localization including dural tears and spinal nerve diverticula. It is the technique with the highest temporal resolution, is robust to breathing artifacts, allows great flexibility regarding patient positioning, compares favorably to other dynamic examinations with respect to the radiation dose and does not require general anesthesia. For CSF venous fistulas, however, other dynamic examinations, such as digital subtraction myelography, seem more appropriate.

Spontaneous intracranial hypotension (SIH) is an important secondary cause of a persistent headache syndrome, classically presenting as sudden onset debilitating positional headaches related to reduced intracranial cerebrospinal fluid (CSF) volume. Current understanding of SIH pathogenesis recognizes three underlying etiologies: dural tear, meningeal diverticulum, and CSF-venous fistula, with a fourth broad category of indeterminate/unknown etiologies. Post-dural puncture headache (PDPH) is a well-known and common complication of dural puncture, typically remitting spontaneously within two weeks of onset or with autologous epidural blood patch, though with some patients developing complex and difficult to manage chronic PDPH. Herein, we present a case of chronic PDPH resulting in SIH symptomatology secondary to a post-dural puncture pseudomeningocele, or “arachnoid bleb,” successfully treated with curative surgical intervention. Increasing awareness of additional potential etiologies of SIH symptomatology will allow for improved detection for targeted definitive therapy, ultimately improving patient outcomes including quality of life in this debilitating and difficult to manage secondary headache syndrome.

ZusammenfassungDas Liquorverlustsyndrom kann nach spinalen Interventionen, wie zum Beispiel Operationen und Punktionen, oder spontan (ohne erkennbare Ursache) auftreten. Durch ein vermindertes Liquorvolumen können intrakranielle Komplikationen entstehen, deren Spektrum von lageabhängigen (orthostatischen) Kopfschmerzen bis hin zu intrakraniellen Blutungen mit lebensbedrohlichen Zuständen reicht. Deshalb ist es wichtig, das Liquorverlussyndrom klinisch richtig einzuordnen, eine gezielte Diagnostik durchzuführen und die adäquate Therapie einzuleiten. Anhand der verschiedenen Ätiologien der Liquorverlustsyndrome und der Schwere der Befunde wird das diagnostische und therapeutische Management dargelegt.

Purpose To propose a modified dynamic CT myelographic technique to locate cerebrospinal fluid (CSF) leaks, also known as cryptogenic leaks, in patients with spontaneous intracranial hypotension (SIH) in whom previous imaging did not show the dural breach. Materials and Methods This retrospective analysis included 74 consecutive patients with SIH and a myelographically proven CSF leak who were evaluated between February 2013 and October 2017. In 14 patients, dynamic CT myelography in the prone or lateral position showed the exact leakage point after unsuccessful previous imaging. During image analysis, the first time point showing extrathecal contrast material was defined as the site of dural breach point. Results Mean population age was 44 years (range, 25-65 years [nine women; mean age, 44 years; age range, 25-65 years] [five men; mean age, 46 years; age range, 29-61 years]). All patients had previously undergone spine MRI, conventional dynamic myelography, and CT myelography. Subsequent dynamic CT myelography covered a mean range of seven vertebral levels. The leak was caused by a calcified microspur in 10 patients and by a dural tear at the axilla of a spinal nerve root in the remaining four. The mean volume CT dose index of dynamic CT myelography was 107 mGy (range, 12-246 mGy), and the mean dose-length product was 1347 mGy·cm (range, 550-3750 mGy·cm). Conclusion Dynamic CT myelography is a valuable adjunctive tool with which to identify the precise location of a dural tear when other examinations are unsuccessful. © RSNA, 2018 See also the editorial by Dillon in this issue.

Objective Spinal cerebrospinal fluid (CSF) leaks cause spontaneous intracranial hypotension (SIH). Microsurgery can sufficiently seal spinal CSF leaks. Yet, some patients suffer from residual symptoms. Aim of the study was to assess predictors for favorable outcome after surgical treatment of SIH. Methods We included consecutive patients with SIH treated surgically from January 2013 to May 2020. Subjects were surveyed by a questionnaire. Primary outcome was resolution of symptoms as rated by the patient. Secondary outcome was postoperative headache intensity on the numeric rating scale (NRS). Association between variables and outcome was assessed using univariate and multivariate regression. A cut-off value for continuous variables was calculated by a ROC analysis. Results Sixty-nine out of 86 patients (80.2%) returned the questionnaire and were analyzed. Mean age was 46.7 years and 68.1% were female. A significant association with the primary and secondary outcome was found only for preoperative symptom duration (p = 0.001 and p p = 0.013). Neither sex, age, type of pathology, lumbar opening pressure, nor initial presentation were associated with the primary outcome. ROC analysis yielded treatment within 12 weeks as a cut-off for better outcome. Conclusion Shorter duration of preoperative symptoms is the most powerful predictor of favorable outcome after surgical treatment of SIH. While an initial attempt of conservative treatment is justified, we advocate early definitive treatment within 12 weeks in case of persisting symptoms.

ObjectiveAnterior Cervical Discectomy and Arthroplasty (ACDA) is an established treatment for degenerative cervical disc disease and seems to be an alternative to fusion in minimizing the risk of Adjacent Segment Disease (ASD). The ROTAIO® cervical disc prosthesis is a novel unconstrained implant with a variable center of rotation aiming at physiological motion. The objective of this multicenter prospective trial was to evaluate clinical outcome and complications within 2 years.Material and Methods120 patients (72 females and 48 males with a median age of 43.0 years; range: 23 to 60 years) underwent ACDA (ROTAIO®, SIGNUS Medical, Alzenau, Germany) and were prospectively followed for 24 months. Preoperative complaints were mainly associated with radiculopathy (n=104) or myelopathy (n=16). There were 108 monosegmental and 12 bisegmental procedures including 6 hybrid constructs. Clinical outcome was evaluated at 3, 12 and 24 months by the Visual Analogue Scale (VAS) for head, neck and arm pain, the Neck Disability Index (NDI), the Work Limitation Questionnaire (WL-26), the Patient`s Satisfaction Index (PSI) and a Quality of Life Questionnaire (SF-36). The Nurick Score, the Modified Japanese Orthopaedic Association Score (mJOA) plus a Composite Success Rate have been additionally applied. Finally, complications, the patient`s overall satisfaction and the amount of analgesics were assessed. ResultsHighly significant clinical improvements were observed according to NDI and VAS (pConclusionThe ROTAIO® cervical disc prosthesis is a safe and efficient treatment option for symptomatic degenerative disc disease demonstrating excellent clinical results at 2 years. Outcome proves to be stable over time with very low revision rates.

Purpose To assess early renal pelvis opacification on postmyelography computed tomography (CT) as a marker for cerebrospinal fluid (CSF) loss in patients with spontaneous intracranial hypotension (SIH). Methods The SIH patients referred to our hospital between January 2012 and May 2018 were retrospectively reviewed and divided into 2 groups based on the presence of spinal longitudinal extrathecal CSF collection (SLEC): (1) SLEC(+) with, and (2) SLEC(−) without proof of SLEC on multimodal imaging. Non-SIH patients (n = 20) undergoing CT myelography served as controls. The renal pelvis density on postmyelography CT was measured in all patients. Mean difference in renal pelvis density between the groups was calculated. Results In total, 111 SIH patients (mean age 48 ± 13 years; 60% female) were included, 71 (64%) SLEC(+) and 40 (36%) SLEC(−). The adjusted renal pelvis density in the SLEC(+), SLEC(−), and the non-SIH group was 108 Hounsfield unit (HU), 83 HU, and 32 HU, respectively, resulting in a significant difference between SLEC(+) vs. control group 1 (75 HU, p p p = 0.16). Conclusion Increased renal pelvis opacification on postmyelography CT was observed in SIH patients, even in the absence of a CSF leak or a CSF venous fistula, when compared to non-SIH patients. Although the provenance of early renal opacification in SLEC (−) SIH patients remains unclear, our results suggest that it may be a surrogate for increased spinal CSF resorption via spinal arachnoid granulations and along spinal nerve sheaths occult to direct imaging.

OBJECTIVE CSF leaks are common complications of spinal and cranial surgeries. Several dural grafts and suture techniques are available to achieve watertight dural closure, but the effectiveness of these techniques remains unclear. The authors developed a standardized in vitro model to test available grafts and suture techniques alone or in combination to find the technique with the most watertight dural closure. METHODS A fluid chamber with a dural fixation device, infusion pump, pressure gauge, and porcine pericardium as a dural equivalent was assembled to provide the reusable device for testing. The authors performed dural closure in 4 different fashions, as follows: A) using running versus simple interrupted suture technique and different suture materials to close a 3-cm incision; B) selecting commonly used sealants and dural patches in combination with a running suture; C) performing duraplasty (1.5 × 1.5–cm square defect) with different dural substitutes in a stand-alone fashion; and D) performing duraplasty with different dural substitutes in a double-layer fashion. Each technique was tested 6 times. The hydrostatic burst pressure (BP) was measured and compared using the Kruskal-Wallis test or the Mann-Whitney U-test. Values are reported as mean ± SD. RESULTS There was no significant difference between the running and simple interrupted suture technique (p = 0.79). Adding a patch or sealant to a suture resulted in a 1.7- to 14-fold higher BP compared to solitary suture closure (36.2 ± 24.27 cm H2O and 4.58 ± 1.41 cm H2O, respectively; p < 0.001). The highest BP was achieved by adding DuraSeal or TachoSil (82.33 ± 12.72 cm H2O and 74.17 ± 12.64 cm H2O, respectively). For closing a square defect, using a double-layer duraplasty significantly increased BP by a factor of 4–12 compared to a single-layer duraplasty (31.71 ± 12.62 cm H2O vs 4.19 ± 0.88 cm H2O, respectively; p < 0.001). The highest BP was achieved with the combination of Lyomesh and TachoSil (43.67 ± 11.45 cm H2O). CONCLUSIONS A standardized in vitro model helps to objectify the watertightness of dural closure. It allows testing of sutures and dural grafts alone or in combination. In the authors’ testing, a running 6-0 monofilament polypropylene suture combined with DuraSeal or TachoSil was the technique achieving the highest BP. For the duraplasty of square defects, the double-layer technique showed the highest efficacy.

BACKGROUND AND PURPOSE: Spine MR imaging plays a pivotal role in the diagnostic work-up of spontaneous intracranial hypotension. The aim of this study was to compare the diagnostic accuracy of unenhanced spine MR imaging and intrathecal gadolinium-enhanced spine MR imaging for identification and localization of CSF leaks in patients with spontaneous intracranial hypotension. MATERIALS AND METHODS: A retrospective study of patients with spontaneous intracranial hypotension examined from February 2013 to October 2017 was conducted. Their spine MR imaging was reviewed by 3 blinded readers for the presence of epidural CSF using 3 different sequences (T2WI, 3D T2WI fat-saturated, T1WI gadolinium). In patients with leaks, the presumed level of the leak was reported. RESULTS: In total, 103 patients with spontaneous intracranial hypotension (63/103 [61%] women; mean age, 50 years) were evaluated. Seventy had a confirmed CSF leak (57/70 [81%] proved intraoperatively), and 33 showed no epidural CSF on multimodal imaging. Intrathecal gadolinium-enhanced spine MR imaging was nonsuperior to unenhanced spine MR imaging for the detection of epidural CSF (P = .24 and .97). All MR imaging sequences had a low accuracy for leak localization. In all patients, only 1 leakage point was present, albeit multiple suspicious lesions were reported in all sequences (mean, 5.0). CONCLUSIONS: Intrathecal gadolinium-enhanced spine MR imaging does not improve the diagnostic accuracy for the detection of epidural CSF. Thus, it lacks a rationale to be included in the routine spontaneous intracranial hypotension work-up. Heavily T2-weighted images with fat saturation provide high accuracy for the detection of an epidural CSF collection. Low accuracy for leak localization is due to an extensive CSF collection spanning several vertebrae (false localizing sign), lack of temporal resolution, and a multiplicity of suspicious lesions, albeit only a single leakage site is present. Thus, dynamic examination is mandatory before targeted treatment is initiated.

BACKGROUND Spinal cerebrospinal fluid (CSF) leaks are the cause of spontaneous intracranial hypotension (SIH). OBJECTIVE To propose a surgical strategy, stratified according to anatomic location of the leak, for sealing all CSF leaks around the 360° circumference of the dura through a single tailored posterior approach. METHODS All consecutive SIH patients undergoing spinal surgery were included. The anatomic site of the leak was exactly localized. We used a tailored hemilaminotomy and intraoperative neurophysiological monitoring (IOM) for all cases. Neurological status was assessed before and up to 90 d after surgery. RESULTS Forty-seven SIH patients had an identified CSF leak between the levels C6 and L1. Leaks, anterior to the spinal cord, were approached by a transdural trajectory (n = 28). Leaks lateral to the spinal cord by a direct extradural trajectory (n = 17) and foraminal leaks by a foraminal microsurgical trajectory (n = 2). The transdural trajectory necessitated cutting the dentate ligament accompanied by elevation and rotation of the spinal cord under continuous neuromonitoring (spinal cord release maneuver, SCRM). Four patients had transient defiticts, none had permanent neurological deficits. We propose an anatomic classification of CSF leaks into I ventral (77%, anterior dural sac), II lateral (19%, including nerve root exit, lateral, and dorsal dural sac), and III foraminal (4%). CONCLUSION Safe sealing (with IOM) of all CSF leaks around the 360° surface of the dura is feasible through a single posterior approach. The exact surgical trajectory is selected according to the anatomic category of the leak.

Le syndrome de la queue de cheval est une rarete absolue et c’est notamment la raison pour laquelle, dans la pratique, il confronte les cliniciens a un defi ne devant pas etre sous-estime.

Das Cauda-equina-Syndrom ist ein sehr seltenes, aber schwerwiegendes neurologisches Zustandsbild. Ursächlich ist zumeist ein raumfordernder Prozess im lumbosakralen Spinalkanal mit Kompression der Cauda-equina-Fasern mit akuten neurologischen Ausfallserscheinungen. Eine frühzeitige Diagnosestellung und Therapie sind essentiell, um permanente und gravierende Funktionsstörungen zu vermeiden.

Zervikale und lumbale Radikulopathien sind meistens Folgeerscheinungen einer degenerativen Wirbelsäulenerkrankung. Klinisch imponieren häufig typische radikuläre Syndrome, die akut oder chronisch, leicht oder schwerwiegend ausfallen können. Bei Versagen der konservativen Therapie bietet die Chirurgie bei sorgfältiger Indikationsstellung gute bis sehr gute Erfolgsaussichten

Les radiculopathies cervicales et lombaires sont le plus souvent les consequences d’une affection degenerative de la colonne vertebrale (syndromes radiculaires typiques, evolution aigue ou chronique, legere ou severe).

STUDY DESIGN Retrospective single-center cohort study. OBJECTIVE The aim of this study was to analyze the influence of preoperative radiographic parameters on reoperation rates after microsurgical laminotomy for lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA Decompression for symptomatic LSS has shown to be effective. However, the optimal surgical strategy remains a matter of debate, especially with underlying spondylolisthesis. METHODS Adult patients with LSS who underwent primary laminotomy without fusion between January 2012 and September 2013 at our institution were included for analysis. Disc height (in mm), facet joint orientation (degrees) and grade of spondylolisthesis of all surgical index levels (SILs) were analyzed from preoperative magnetic resonance imaging. Patients were contacted in January 2017 by follow-up phone call (mean follow-up 49 months) regarding lumbar reoperation. RESULTS A total of 161 patients (mean age 68.5 years, ±11.3) and 236 SILs were analyzed. Fifty-six patients (34.8%) had low-grade spondylolisthesis involving 60 SILs (25.4%). Twenty-four patients (14.9%) underwent reoperation involving 32 levels. Of latter, 23 SILs (9.7%) had recurrent stenosis and 9 (3.8%) had adjacent level stenosis. Five patients in total (3.1%) required secondary fusion; all had preexisting spondylolisthesis. SILs with spondylolisthesis had a significantly higher rate of recurrent stenosis requiring reoperation compared to SILs without spondylolisthesis (18.3% (11/60) vs. 6.8% (12/176), p = 0.013). Disc height and facet joint orientation showed no significant difference between patients with and without reoperation, or with and without spondylolisthesis. CONCLUSIONS Decompression alone is reasonable for most patients with LSS and stable low-grade spondylolisthesis. The overall reoperation rate and need for secondary fusion were low in our series. However, patients with spondylolisthesis had a higher rate of reoperation for recurrent stenosis after laminotomy without fusion. This must be taken into account for preoperative risk-benefit analysis, tailored surgical decision-making and patient counseling. LEVEL OF EVIDENCE 4.

BackgroundPostural orthostatic tachycardia syndrome is a disorder of the autonomic nervous system. Approximately 30% of patients experience orthostatic headaches. Orthostatic headaches also are a hallmark symptom in spontaneous intracranial hypotension. While the cause of orthostatic headaches in spontaneous intracranial hypotension can be linked to the cerebrospinal fluid loss at the spinal level and consecutively reduced intracranial pressure in the upright position, the cause of orthostatic headaches in postural orthostatic tachycardia syndrome still remains unknown. The present study examined orthostatic changes of intracranial pressure using dynamic ultrasound of the optic nerve and optic nerve sheath diameter in postural orthostatic tachycardia syndrome, spontaneous intracranial hypotension and healthy subjects.MethodsData was obtained from postural orthostatic tachycardia syndrome patients with (n = 7) and without orthostatic headaches (n = 7), spontaneous intracranial hypotension patients (n = 5) and healthy subjects (n = 8). All participants underwent high-resolution transorbital ultrasound in the supine and upright position to assess optic nerve and optic nerve sheath diameter.ResultsGroup differences were found in percentage deviations when changing position of optic nerve sheath diameter (p < 0.01), but not regarding the optic nerve diameter. Pairwise comparisons indicated differences in optic nerve sheath diameter only between spontaneous intracranial hypotension and the other groups. No differences were found between postural orthostatic tachycardia syndrome patients with and without orthostatic headaches.ConclusionThis study shows that the size of the optic nerve sheath diameter dynamically decreases during orthostatic stress in spontaneous intracranial hypotension, but not in postural orthostatic tachycardia syndrome with or without orthostatic headaches, which indicates different underlying causes.

Objective: To visualize and treat spinal dural CSF leaks in all patients with intractable spontaneous intracranial hypotension (SIH) who underwent spinal microsurgical exploration. Methods: Patients presenting between February 2013 and July 2015 were included in this consecutive case series. The workup included spinal MRI without and with intrathecal contrast, dynamic myelography, postmyelography CT, and microsurgical exploration. Results: Of 69 consecutive patients, 15 had intractable symptoms. Systematic imaging revealed a suspicious single location of the leak in these 15 patients. Fourteen patients underwent microsurgical exploration; 1 patient refused surgery. Intraoperatively, including intradural exploration, we identified the cause of the CSF leaks as a longitudinal dural slit (6.1 ± 1.7 mm) on the ventral (10), lateral (3), or dorsal (1) aspect of the dura. In 10 patients (71%), a ventral, calcified microspur originating from the intervertebral disk perforated the dura like a knife. Three patients (22%) had a lateral dural tear with an associated spinal meningeal diverticulum, and in 1 patient (7%), a dorsal osteophyte was causal. The microspurs were removed and the dural slits sutured with immediate cessation of CSF leakage. Conclusion: The nature of the CSF leak is a circumscribed longitudinal slit at the ventral, lateral, or dorsal dura mater. An extradural pathology, diskogenic microspurs, was the single cause for all ventral CSF leaks. These findings challenge the notion that CSF leaks in SIH are idiopathic or due to a weak dura. Microsurgery is the treatment of choice in cases with intractable SIH.

Objective Spontaneous intracranial hypotension is caused by spinal cerebrospinal fluid leakage. Patients with orthostatic headaches and cerebrospinal fluid leakage show a decrease in optic nerve sheath diameter upon movement from supine to upright position. We hypothesized that the decrease in optic nerve sheath diameter upon gravitational challenge would cease after closure of the leak. Methods We included 29 patients with spontaneous intracranial hypotension and refractory symptoms admitted from 2013 to 2016. The systematic workup included: Optic nerve sheath diameter sonography, spinal MRI and dynamic myelography with subsequent CT. Microsurgical sealing of the cerebrospinal fluid leak was the aim in all cases. Results Of 29 patients with a proven cerebrospinal fluid leak, one declined surgery. A single patient was lost to follow-up. In 27 cases, the cerebrospinal fluid leak was successfully sealed by microsurgery. The width of the optic nerve sheath diameter in supine position increased from 5.08 ± 0.66 mm before to 5.36 ± 0.53 mm after surgery ( p = 0.03). Comparing the response of the optic nerve sheath diameter to gravitational challenge, there was a significant change from before (−0.36 ± 0.32 mm) to after surgery (0.00 ± 0.19 mm, p Conclusions The sonographic assessment of the optic nerve sheath diameter with gravitational challenge can distinguish open from closed spinal cerebrospinal fluid fistulas in spontaneous intracranial hypotension patients. A response to the gravitational challenge, that is, no more collapse of the optic nerve sheath while standing up, can be seen after successful treatment and correlates with the resolution of clinical symptoms. Sonography of the optic nerve sheath diameter may be utilized for non-invasive follow-up in spontaneous intracranial hypotension.

Aims: Surgical decompression for lumbar spinal stenosis (LSS) causing symptomatic neurogenic claudication has shown to be effective. However, the optimal surgical strategy remains a matter of debate, especially in the presence of concomitant low-grade spondylolisthesis (LGS). We aimed to analyze the influence of preoperative anatomical parameters in patients who underwent selective decompression for LSS in terms of reoperation within 4 years. Methods: This is a single-center cohort study of adult patients with symptomatic LSS who underwent primary decompression without fusion between January 2012 and September 2013 at our institution. Disc height (in mm), facet joint orientation (degrees), and Meyerding grade (0–4) of spondylolisthesis of all index levels (ILs) were analyzed from preoperative magnetic resonance imaging. Patients were contacted 4 years after surgery by follow-up phone call regarding revision surgery of ILs or adjacent levels. For subgroup analysis, ILs not revised (group 1) were compared with ILs that did require revision (group 2). Results: A total of 162 patients (95 men, 67 women, mean age 68.6 years, ± 11.3) were included into the study and a total of 237 ILs in the lumbar spine were analyzed. LGS was present in 25.3% of ILs (60 ILs); there were no ILs with high-grade spondylolisthesis. Twenty-five patients (15.4%) underwent a second lumbar decompression surgery within 4 years involving 34 levels (13.9%). Of these, 24 ILs (10.1%) had recurrent stenosis and 10 (4.2%) had adjacent segment stenosis. Five patients (20%) were revised with decompression and instrumented fusion, and four of these had LGS. ILs with LGS had a significantly higher rate of recurrent stenosis that required revision compared with ILs without spondylolisthesis (18.3% [11/60] versus 7.3% [13/177], p = 0.0148, odds ratio 2.832, 95% confidence interval 1.233–6.899). Disc height and facet joint orientation of ILs showed no statistically significant difference between groups 1 and 2. Conclusions: Concomitant LGS is an important risk factor for recurrent stenosis after decompression of LSS without fusion. This must be taken into account for preoperative surgical planning and patient counseling.

Background and purpose: Orthostatic headache is a hallmark of patients with spontaneous intracranial hypotension (SIH) but may also occur in patients with postural tachycardia syndrome (POTS). Our aim was to compare the clinical symptoms and findings of autonomic function testing in patients with SIH and POTS. Methods: This was a retrospective analysis of the clinical symptoms and findings of autonomic function testing, including sympathetic vasoconstrictor and parasympathetic cardiac function as well as head-up tilt in patients with SIH and POTS. Results: Nine patients with confirmed SIH and 48 with POTS (neuropathic N = 35, hyperadrenergic N = 5, deconditioned N = 8) were included. SIH patients experienced on average a shorter disease duration than patients with POTS. Orthostatic headache was present in all patients with SIH and 27% of patients with POTS. There was a broad overlap of other clinical symptoms of orthostatic intolerance. Screening autonomic function testing revealed normal sympathetic and parasympathetic function in all patients. All patients with SIH showed an excessive clinically symptomatic heart rate increase during standing, fulfilling the diagnostic criteria for POTS. Conclusion: Clinical symptoms and results of autonomic function testing overlap in SIH and POTS. Hence, patients with prominent orthostatic headache fulfilling the diagnostic criteria for POTS should also be evaluated for further testing of a spinal cerebrospinal fluid leak, in the absence of a history of lumbar puncture.

Background: Various signs may be observed on brain magnetic resonance imaging (MRI) in patients with spontaneous intracranial hypotension (SIH). However, the lack of a classification system integrating these findings limits decision making in clinical practice. The objective was to assess the likelihood of an underlying spinal CSF leak based on a probability score taking into account the most relevant brain MRI findings. Methods: Three blinded readers retrospectively reviewed the brain MRI of 56 SIH patients with a proven spinal CSF leak and 60 healthy controls, evaluating seven quantitative and nine qualitative signs. We then derived a predictive diagnostic score based on multivariable backward logistic regression analysis. Its performance was further validated internally in a prospective cohort of 20 patients presenting with clinical signs of SIH. Findings: Six imaging findings were included in the final scoring system. Three were weighted as major (2 points): pachymeningeal enhancement, engorgement of venous sinus, effacement of the suprasellar cistern 5, respectively. The discriminatory ability of the proposed score could be demonstrated in the validation cohort. Interpretation: The three-tier predictive scoring system we propose is based on the six most relevant brain MRI findings and allows to assess the likelihood (low, intermediate or high probability) of finding a spinal CSF leak in SIH patients. It may be useful in triaging patients who may or may not benefit from further invasive myelographic examinations before considering targeted therapy. Funding Statement: The authors declare: "This study was not funded, as all examinations were part of our routine clinical protocol." Declaration of Interests: PJM receives Swiss National Science Foundation (SNSF) grants for research on brain aneurysms. JG is a global PI of STAR, CEC member of the PROMISE study (Penumbra) PI for the SWIFT DIRECT study (Medtronic), Consultancy; and receives Swiss National Science Foundation (SNSF) grants for magnetic resonance imaging in stroke. JB is global PI of SWITCH and TOSCAN studies. He received SNSF grant for ultrasound perfusion imaging. All other authors declare no competing interests. Ethics Approval Statement: Institutional review board approval was obtained for this single-center study (Kantonale Ethikkommission Bern, Switzerland, number: 2017–00861).

A 36-year-old man was diagnosed with Langerhans cell histiocytosis (LCH) of the cervical spine with a unifocal expansive osteolytic lesion of C4. The surgical management with a 2-year follow-up and a review of the literature on LCH of the cervical spine are presented. Although a rare condition, LCH is an important differential diagnosis of any osteolytic lesion in the cervical spine with localized pain in a young adult patient. Review of the literature suggests a higher prevalence of LCH lesions affecting the cervical spine as compared with the thoracic or lumbar spine than historically reported.

Background and purpose: Orthostatic headache is a hallmark of patients with spontaneous intracranial hypotension (SIH) but may also occur in patients with postural tachycardia syndrome (POTS). Our aim was to compare the clinical symptoms and findings of autonomic function testing in patients with SIH and POTS. Methods: This was a retrospective analysis of the clinical symptoms and findings of autonomic function testing, including sympathetic vasoconstrictor and parasympathetic cardiac function as well as head-up tilt in patients with SIH and POTS. Results: Nine patients with confirmed SIH and 48 with POTS (neuropathic N = 35, hyperadrenergic N = 5, deconditioned N = 8) were included. SIH patients experienced on average a shorter disease duration than patients with POTS. Orthostatic headache was present in all patients with SIH and 27% of patients with POTS. There was a broad overlap of other clinical symptoms of orthostatic intolerance. Screening autonomic function testing revealed normal sympathetic and parasympathetic function in all patients. All patients with SIH showed an excessive clinically symptomatic heart rate increase during standing, fulfilling the diagnostic criteria for POTS. Conclusion: Clinical symptoms and results of autonomic function testing overlap in SIH and POTS. Hence, patients with prominent orthostatic headache fulfilling the diagnostic criteria for POTS should also be evaluated for further testing of a spinal cerebrospinal fluid leak, in the absence of a history of lumbar puncture.

Background Despite multiple advantages of minimally invasive techniques in spinal surgery, the currently used approaches may lead to postoperative pain and spinal instability. As a natural orifice, the hiatus sacralis offers a nontransmuscular alternative entry point for endoscopic approaches. In this study, we collected data about the complex anatomical conditions of the sacral canal as a basis for the development of a sacral endoscope. Methods We retrospectively evaluated 192 postmortem human cadaveric specimens with computed tomography (CT). The anatomical conditions of the sacrum and lumbar spine were analyzed, including assessment of the lateral and anteroposterior diameters, measurement of the cross-sectional area of the sacral canal at the lumbosacral transition, hiatus sacralis, and the narrowest point of the sacral canal. Results The narrowest anteroposterior diameter was >2.3 mm in 95% of the cases; the width was >13 mm in 95% of the cases. The narrowest point was located at the hiatus in 72% of the cases. The angle of sacral kyphosis was less than 30° and less than 50° in lumbar lordosis in 95% of the cases. A length shorter than 288 mm was measured in 95% of the cases. Anatomical conditions in male and female sacra were comparable. Conclusions The narrow anteroposterior diameter is the key limiting feature for using the canalis sacralis as a natural entry point into the spinal canal. Sacroscopy will require endoscopes with a flattened shape, with parallel arrangement of instruments and flexibility to accommodate the varied dorsal and ventral curvatures.

Patients with complaints and symptoms caused by spinal degenerative diseases demonstrate a high rate of spontaneous improvement. Except of severe neurological symptoms such as high grade motor deficits, medically intractable pain and vegetative symptoms (cauda syndrome) operations require 1) symptoms, 2) a mechanical cause visible on imaging that sufficiently explains the symptoms, 3) a completed conservative treatment protocol performed over a 4) 6-12 week period. According to the evidence found in the literature, patients with lumbar disk herniation significantly benefit from surgery by a faster relieve of pain and return to social and professional activity, however, the results are converging after a period of 1-2 years. Surgery of lumbar spinal stenosis is considered a gold standard and superior to conservative care when symptoms are severe and leg pain is present. Bilateral microsurgical decompression using a bilateral or a unilateral approach with over-the-top decompression of the contralateral nerve root are superior to laminectomy as the decompression procedure. Lumbar fusion is only indicated in patients with spinal stenosis when a major or mobile spondylolisthesis is diagnosed. There is no indication of prophylactic surgery to avoid a "dangerous" deficit that might develop in the future.

Object The etiology of chronic subdural hematoma (CSDH) in nongeriatric patients (≤ 60 years old) often remains unclear. The primary objective of this study was to identify spinal CSF leaks in young patients, after formulating the hypothesis that spinal CSF leaks are causally related to CSDH. Methods All consecutive patients 60 years of age or younger who underwent operations for CSDH between September 2009 and April 2011 at Bern University Hospital were included in this prospective cohort study. The patient workup included an extended search for a spinal CSF leak using a systematic algorithm: MRI of the spinal axis with or without intrathecal contrast application, myelography/fluoroscopy, and postmyelography CT. Spinal pathologies were classified according to direct proof of CSF outflow from the intrathecal to the extrathecal space, presence of extrathecal fluid accumulation, presence of spinal meningeal cysts, or no pathological findings. The primary outcome was proof of a CSF leak. Results Twenty-seven patients, with a mean age of 49.6 ± 9.2 years, underwent operations for CSDH. Hematomas were unilateral in 20 patients and bilateral in 7 patients. In 7 (25.9%) of 27 patients, spinal CSF leakage was proven, in 9 patients (33.3%) spinal meningeal cysts in the cervicothoracic region were found, and 3 patients (11.1%) had spinal cysts in the sacral region. The remaining 8 patients (29.6%) showed no pathological findings. Conclusions The direct proof of spinal CSF leakage in 25.9% of patients suggests that spinal CSF leaks may be a frequent cause of nongeriatric CSDH.

Idiopathic spinal cord herniation (ISCH) through an anterior dural defect is rare and the cause is uncertain. Recently, through interpreting imaging studies, disc herniation was proposed to be a major cause for ISCH. We describe the case of a 50-year-old woman with progressive myelopathy who was diagnosed with a thoracic spinal cord herniation. Microsurgical exploration revealed an anterior vertical dural defect and a small concomitant disc herniation, occult on the preoperative imaging, which caused the dural defect and led to ISCH. This intraoperative finding corroborates the emerging notion that disc herniation is the underlying cause of ISCH.

OBJECTIVESpinal CSF leakage causes spontaneous intracranial hypotension (SIH). The aim of this study was to characterize CSF dynamics via lumbar infusion testing in patients with and without proven spinal CSF leakage in order to explore possible discriminators for the presence of an open CSF leak.METHODSThis analysis included all patients with suspected SIH who were treated at the authors’ institution between January 2012 and February 2015. The gold standard for “proven” CSF leakage is considered to be extrathecal contrast accumulation after intrathecal contrast injection. To characterize CSF dynamics, the authors performed computerized lumbar infusion testing to measure lumbar pressure at baseline (opening pressure) and at plateau, as well as pulse amplitude, CSF outflow resistance (RCSF), craniospinal elastance, and pressure-volume index.RESULTSThirty-one patients underwent clinical imaging and lumbar infusion testing and were included in the final analysis. A comparison of the 14 patients with proven CSF leakage with the 17 patients without leakage showed a statistically significantly lower lumbar opening pressure (p < 0.001), plateau pressure (p < 0.001), and RCSF (p < 0.001) in the group with leakage. Sensitivity, specificity, and positive and negative predictive values for an RCSF cutoff of ≤ 5 mm Hg/(ml/min) were 0.86, 1.0, 1.0, and 0.89 (area under the curve of 0.96), respectively. The median pressure-volume index was higher (p = 0.003), and baseline (p = 0.017) and plateau (p < 0.001) pulse amplitudes were lower in patients with a proven leak.CONCLUSIONSLumbar infusion testing captures a distinct pattern of CSF dynamics associated with spinal CSF leakage. RCSF assessed by computerized lumbar infusion testing has an excellent diagnostic accuracy and is more accurate than evaluating the lumbar opening pressure. The authors suggest inclusion of RCSF in the diagnostic criteria for SIH.

Importance Various signs may be observed on brain magnetic resonance imaging (MRI) in patients with spontaneous intracranial hypotension (SIH). However, the lack of a classification system integrating these findings limits decision making in clinical practice. Objective To develop a probability score based on the most relevant brain MRI findings to assess the likelihood of an underlying spinal cerebrospinal fluid (CSF) leak in patients with SIH. Design, Setting, and Participants This case-control study in consecutive patients investigated for SIH was conducted at a single hospital department from February 2013 to October 2017. Patients with missing brain MRI data were excluded. Three blinded readers retrospectively reviewed the brain MRI scans of patients with SIH and a spinal CSF leak, patients with orthostatic headache without a CSF leak, and healthy control participants, evaluating 9 quantitative and 7 qualitative signs. A predictive diagnostic score based on multivariable backward logistic regression analysis was then derived. Its performance was validated internally in a prospective cohort of patients who had clinical suspicion for SIH. Main Outcomes and Measures Likelihood of a spinal CSF leak based on the proposed diagnostic score. Results A total of 152 participants (101 female [66.4%]; mean [SD] age, 46.1 [14.3] years) were studied. These included 56 with SIH and a spinal CSF leak, 16 with orthostatic headache without a CSF leak, 60 control participants, and 20 patients in the validation cohort. Six imaging findings were included in the final scoring system. Three were weighted as major (2 points each): pachymeningeal enhancement, engorgement of venous sinus, and effacement of the suprasellar cistern of 4.0 mm or less. Three were considered minor (1 point each): subdural fluid collection, effacement of the prepontine cistern of 5.0 mm or less, and mamillopontine distance of 6.5 mm or less. Patients were classified into groups at low, intermediate, or high probability of having a spinal CSF leak, with total scores of 2 points or fewer, 3 to 4 points, and 5 points or more, respectively, on a scale of 9 points. The discriminatory ability of the proposed score could be demonstrated in the validation cohort. Conclusions and Relevance This 3-tier predictive scoring system is based on the 6 most relevant brain MRI findings and allows assessment of the likelihood (low, intermediate, or high) of a positive spinal imaging result in patients with SIH. It may be useful in identifying patients with SIH who are leak positive and in whom further invasive myelographic examinations are warranted before considering targeted therapy.

An 89-year old man with known ankylosing spondylitis (AS) had undergone ventral corpectomy, implantation of a PEEK (polyetheretherketone) cage, and ventral fusion after suffering a dislocated compression fracture of C-7 (Fig. 1A); stabilization was subsequently achieved by dorsal C5–6 and T1–2 fusion (Fig. 1B). The patient had no neurological deficits. Eighteen months later the man presented with massive atrophy of paraspinal muscles and protrusion of spinous processes (Fig. 1C and D). Open resection of the C-7, T-1, and T-2 spinous processes was performed. The overlying skin and atrophic scar tissue were removed (Fig. 1E and F). Adaptation to the bone of paraspinal muscles was not possible due to atrophy. Six weeks after surgery, efficient wound healing was observed (Fig. 1G). Satisfactory cosmesis was achieved, and no infection developed. Neither complications of wound healing nor related to the fracture occurred within the 6-month follow-up period. The patient died 8 months after surgery, with no causal relation between the procedure and death. Atrophic changes leading to paraspinal muscle fibrosis in AS1 appeared to arise from disuse of or neurogenic damage to the posterior branches of the spinal nerves due to bony facet joint encroachment in the neural foramina. This patient with an AS-induced rigid spine had extreme atrophy of the paraspinal muscles that led to direct mechanical exposure of spinous processes. We describe a safe and simple surgical approach—so far lacking in the literature—that prevents potential complications due to wound perforation or skin infection. As ours was a single case, recommendations to prevent this condition are limited.

Spontaneous intracranial hypotension (SIH) has gained more attention in the eyes of clinicians in the past years and is now recognized as an important cause of headaches. While usually self-limiting and benign, some patients suffer from debilitating symptoms that interfere significantly with their social and professional life. Thus, recognition and adequate treatment of SIH is of paramount importance. Recent refinements in imaging techniques combined with modern microneurosurgical techniques offer many diagnostic and therapeutic possibilities today. The aim of this review is to give the reader an updated review on the state-of-the art in the challenging diagnosis and treatment of SIH as well as an insight into recent developments of pathophysiological concepts and affiliations with other enigmatic diseases.