Anterolateral decompression of the atlantoaxial vertebral artery for symptomatic positional occlusion of the vertebral artery. Case report

Atlas Subluxation Complex, National Upper Cervical Chiropractic Association Intervention, and Dizziness Improvement: A Narrative Review of Historical Perspectives, Literature Synthesis, and a Path for Future Care

Dizziness is a non-specific and common condition in which the afflicted individual experiences abnormal sensations such as lightheadedness, imbalance, or a false sense of spinning (vertigo). The experience of "dizziness" can result from a wide spectrum of abnormal physiological states, including exhaustion, hypotension, and hypoglycemia, but could also indicate a serious underlying health issue. Since it has many potential generating causes, accurate identification of the underlying etiology of dizziness can present a challenge to clinicians, often resulting in ineffective treatments. We present a hypothesis that atlas subluxation complex (ASC) may comprise an etiological agent of dizziness that can be successfully addressed with National Upper Cervical Chiropractic Association (NUCCA) chiropractic care. In this review, we discuss the pathophysiology of the ASC, introduce the NUCCA chiropractic procedure, and complete a literature review and synthesis. Conceptual evidence, case reports, and theory provide foundational evidence that the ASC may be a contributory factor of dizziness generation and that NUCCA chiropractic corrective care of the ASC may produce favorable dizziness outcomes. However, high-quality studies are lacking. The foundation evidence provides indication that further research via observational studies and randomized controlled trials (RCTs) is warranted.

Correlation between body mass index and two-stage revision failure of periprosthetic joint infection following total joint arthroplasty: A systematic review and meta-analysis

Background: Although the correlation between body mass index (BMI) and two-stage revision failure of periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) have been frequently reported, the results remain controversial. Therefore, the correlation between them was systematically evaluated and meta-classified in this study. Methods: Literature on the correlation between BMI and two-stage revision failure of PJI following TJA was retrieved in PubMed, Embase and Cochrane Library due May 2020. Stata 13.0 software and Cochrane Collaboration Review Manager software (RevMan version 5.3) were applied to data synthesis, subgroup analysis, analyses of publication bias, and sensitivity. Results: A total of 15 observational studies included 1267 patients, of which 15 studies were included in systematic review and 11 studies in meta-analysis. Eight studies found a correlation between BMI and two-stage revision failure of PJI following TJA, but seven other studies found no correlation. Meta-analysis found that the risk of two-stage revision failure of PJI following TJA significantly boosted by 3.53 times in patients with BMI ≥ 30 kg/m² (OR = 3.53; 95% CI = 1.63-7.64 for the BMI ≥ 30 kg/m² vs. BMI < 30 kg/m²) and the risk of two-stage revision failure of PJI following TJA significantly increased by 2.92 times in patients with BMI ≥ 40 kg/m² (OR = 2.92; 95%CI = 1.06-8.03 for the BMI ≥ 40 kg/m² vs. BMI < 30 kg/m²). The subgroup analysis showed that significant association was observed among the studies performed in TKA (OR = 3.63; 95% CI = 2.27-5.82), but not among those conducted in THA (OR = 3.06; 95% CI = 0.42-22.19). A significant association remained consistent, as indicated by sensitivity analyses. Because there are too few studies that can be combined in the included studies, Egger's and Begg's tests were not performed. Conclusion: Meta-analysis suggests that the risk of two-stage revision failure of PJI following TJA significantly boosted in obese patients. However, because there may be publication bias of this study, combined overall systematically evaluated and meta-analysis results, we cannot yet conclude that BMI is associated with two-stage revision failure of PJI following TJA.

Case Report: Bow Hunter Syndrome—One Reason to Add Non-gravity Dependent Positional Nystagmus Testing to Your Clinical Neuro-Otologic Exam

This case study describes transient downbeat nystagmus with vertigo due to a bilateral Bow Hunters Syndrome that was initially treated for 7 months as a peripheral benign paroxysmal positional vertigo. Normal static angiography and imaging studies (magnetic resonance, computed tomography) contributed to the mis-diagnosis. However, not until positional testing with the patient in upright (non-gravity dependent) was a transient downbeat nystagmus revealed with vertigo. The patient was referred for neurosurgical consult. Unfortunately, surgery was delayed due to suicidal ideation and hospitalization. Eventually, vertigo symptoms resolved following a C4-5 anterior cervical dissection and fusion. This case highlights the critical inclusion of non-gravity dependent position testing as an augment to the positional testing component of the clinical examination as well as the extreme duress that prolonged positional vertigo can cause.

Ischemic Stroke Secondary to Dynamic Vertebral Artery Stenosis: Case Report and Review of the Literature

Ischemic stroke secondary to dynamic vertebral artery stenosis or occlusion, also known as “bow hunter's syndrome,” is a rare stroke mechanism. We report a case of a 24-year-old man with multiple hereditary exostosis (MHE) diagnosed at childhood. His first presentation to a neurologist was due to neck pain and clinical syndrome suggestive of ischemia in the vertebrobasilar territory. A therapeutic occlusion was done successfully without complication. The patient was discharged two days later on aspirin alone. In follow up one year later he continued to be symptom free. Moreover, this stroke mechanism has been reported extensively in the literature in isolation or secondary to many underlying diseases. In total, there are 168 cases reported in the published English literature, in either case reports or small series. In this review, we found that by far, vertebral artery occlusion at the atlanto-axial (C1-2) level dominated most reported cases. The most frequent presentation that led to further investigation was syncope or pre-syncope provoked by head rotation to one side. To our knowledge, there is no previous report of any stroke syndrome related to MHE before our case. In this paper, we report the first case secondary to MHE and review the literature up to date since the first reported case in 1952.

Bow hunter syndrome in rheumatoid arthritis: illustrative case

BACKGROUND

Rheumatoid arthritis (RA) frequently features degeneration and instability of the cervical spine. Rarely, this degeneration manifests as symptoms of bow hunter syndrome (BHS), a dynamic cause of vertebrobasilar insufficiency.

OBSERVATIONS

The authors reviewed the literature for cases of RA associated with BHS and present a case of a man with erosive RA with intermittent syncopal episodes attributable to BHS as a result of severe extrinsic left atlantooccipital vertebral artery compression from RA-associated cranial settling. A 72-year-old man with RA-associated cervical spine disease who experienced gradual, progressive functional decline was referred to a neurosurgery clinic for evaluation. He also experienced intermittent syncopal events and vertiginous symptoms with position changes and head turning. Vascular imaging demonstrated severe left vertebral artery compression between the posterior arch of C1 and the occiput as a result of RA-associated cranial settling. He underwent left C1 hemilaminectomy and C1–4 posterior cervical fusion with subsequent resolution of his syncope and vertiginous symptoms.

LESSONS

This is an unusual case of BHS caused by cranial settling as a result of RA. RA-associated cervical spine disease may rarely present as symptoms of vascular insufficiency. Clinicians should consider the possibility, though rare, of cervical spine involvement in patients with RA experiencing symptoms consistent with vertebral basilar insufficiency.

Transitional nystagmus in a Bow Hunter's Syndrome case report

Background

Bow Hunter’s Syndrome (BHS) is known as one of cervical diseases which causes vertigo, but the details of its vertigo, especially nystagmus and eye movement, are still incompletely understood. This time, we reported the first case of BHS with a nystagmus chart with video record of transitional nystagmus.

Case presentation

The patient, a 47-year-old female, complained of vertigo caused by head rotation. When she turned her head leftward, leftward nystagmus appeared, and this was followed by dullness of the right arm. After her head was returned to the central position, downbeat nystagmus appeared, which changed to rightward nystagmus. She was diagnosed with BHS by her symptoms and images. We recorded a nystagmus video and nystagmus chart of this transitional nystagmus including downbeat nystagmus. Her vertigo was cured by the modification of a prescription for her past medical history: hypertension.

Conclusion

The vertigo of BHS accompanies nystagmus. In this present case, the transitional nystagmus was observed, and it occurred toward the healthy side. Then the nystagmus direction was changed to the affected side via downbeat nystagmus. This is the first report with both a nystagmus chart with video of BHS. Nowadays, various kinds of vertigo induced by neck movement are known. BHS is a rare disease among vertigo diseases, but we should consider it as a different diagnosis of vertigo patients. A precise interview and proper examination are required to make the final diagnosis.

Repetitive transcranial magnetic stimulation on chronic tinnitus: a systematic review and meta-analysis

BACKGROUND

Although the clinical efficacy and safety of repetitive transcranial magnetic stimulation (rTMS) in the treatment of chronic tinnitus have been frequently examined, the results remain contradictory. Therefore, we performed a systematic review and meta-analysed clinical trials examining the effects of rTMS to evaluate its clinical efficacy and safety.

METHODS

Studies of rTMS for chronic tinnitus were retrieved from PubMed, Embase, and Cochrane Library through April 2020. Review Manager 5.3 software was employed for data synthesis, and Stata 13.0 software was used for analyses of publication bias and sensitivity.

RESULTS

Twenty-nine randomized studies involving 1228 chronic tinnitus patients were included. Compared with sham-rTMS, rTMS exhibited significant improvements in the tinnitus handicap inventory (THI) scores at 1 week (mean difference [MD]: - 7.92, 95% confidence interval [CI]: - 14.18, - 1.66), 1 month (MD: -8.52, 95% CI: - 12.49, - 4.55), and 6 months (MD: -6.53, 95% CI: - 11.406, - 1.66) post intervention; there were significant mean changes in THI scores at 1 month (MD: -14.86, 95% CI: - 21.42, - 8.29) and 6 months (MD: -16.37, 95% CI: - 20.64, - 12.11) post intervention, and the tinnitus questionnaire (TQ) score at 1 week post intervention (MD: -8.54, 95% CI: - 15.56, - 1.52). Nonsignificant efficacy of rTMS was found regarding the THI score 2 weeks post intervention (MD: -1.51, 95% CI: - 13.42, - 10.40); the mean change in TQ scores 1 month post intervention (MD: -3.67, 95% CI: - 8.56, 1.22); TQ scores 1 (MD: -8.97, 95% CI: - 20.41, 2.48) and 6 months (MD: -7.02, 95% CI: - 18.18, 4.13) post intervention; and adverse events (odds ratios [OR]: 1.11, 95% CI: 0.51, 2.42). Egger's and Begg's tests indicated no publication bias (P = 0.925).

CONCLUSION

This meta-analysis demonstrated that rTMS is effective for chronic tinnitus; however, its safety needs more validation. Restrained by the insufficient number of included studies and the small sample size, more large randomized double-blind multi-centre trials are needed for further verification.

Correlation between Body Mass Index and Periprosthetic Joint Infection following Total Joint Arthroplasty: A protocol for systematic review and meta analysis

BACKGROUND

Despite rapid reports on the correlation between body mass index (BMI) and periprosthetic joint infection (PJI) after total joint arthroplasty, some have conducted regression tests or meta-analyses with controversial results. In this study, we systematically meta-analyzed relevant trials and carefully evaluated the correlation for verification.

METHODS

Literature on the correlation between BMI and PJI following total joint arthroplasty was retrieved in PubMed, Embase and Cochrane Library due September 2019. Stata 13.0 software was adopted for data synthesis and analyses of publication bias and sensitivity. Random-effect models were used to summary the overall estimate of the multivariate adjusted odds ratio (OR)/hazard ratio/rate ratio with 95% confidence intervals (CIs).

RESULTS

A total of 29 observational studies representing 3,204,887 patients were included. The meta-analysis revealed that the risk of postoperative PJI significantly increased by 1.51 times in the obese group (OR = 1.51; 95% CI = 1.30-1.74 for the obese group vs. the non-obese group), and by 3.27 times in the morbid obese group (OR = 3.27; 95% CI = 2.46-4.34 for the morbid obese group vs the non-morbid obese group). A significant association remained consistent, as indicated by subgroup analyses and sensitivity analyses.

CONCLUSION

Our findings demonstrate that postoperative PJI is positively correlated with BMI, with obese patients showing a greater risk of developing PJI than non-obese patients. Similarly, morbid obese patients present a higher risk of PJI than non-morbid obese patients. However, this conclusion needs to be corroborated by more prospective studies.

Risk factors associated with osteonecrosis of femoral head after internal fixation of femoral neck fracture:a systematic review and meta-analysis

BACKGROUND

Although the risk factors associated with osteonecrosis of femoral head (ONFH) after internal fixation of femoral neck fracture (IFFNF) have been frequently reported, the results remain controversial. Therefore, its related risk factors were systematically evaluated and meta-classified in this study.

METHODS

Literature on risk factors of ONFH caused by IFFNF was retrieved in PubMed, Embase and Cochrane Library due June 2019. Review Manager 5.3 software was applied to data synthesis, and Stata 13.0 software was adopted for analyses of publication bias and sensitivity.

RESULTS

A total of 17 case-control studies with 2065 patients were included. The risk of ONFH after IF was 0.40-fold higher in patients with Garden III-IV FNF than that in patients with Garden I-II (OR: 0.40, 95%CI: 0.29-0.55). The risk of OFNH with retained IF was uplifted by 0.04 times (OR: 0.04, 95%CI: 0.02-0.07). There was nonsignificant relationship between gender and ONFH after IFFNF (OR: 1.27, 95%CI: 0.84-1.94). Moreover, ONFH after IFFNF presented no association with age (OR:1.66, 95%CI: 0.89-3.11), injury-operation interval (OR:1.29, 95%CI: 0.82-2.04), fracture reduction mode (OR:1.98, 95%CI: 0.92-4.26), preoperative traction (OR:1.69, 95%CI: 0.29-9.98) and mechanism of injury (OR:0.53, 95%CI: 0.06-4.83). Egger's and Begg's tests indicated a publication bias (P = 0.001).

CONCLUSION

It was demonstrated that Garden classification and retained IF were important influencing factors of ONFH after IFFNF. Gender, age, injury-operation interval, fracture reduction mode, preoperative traction and the mechanism of ONFH were irrelevant to the complication.

Acupuncture for vertebrobasilar insufficiency vertigo: Protocol for a systematic review and meta-analysis

BACKGROUND

Vertebrobasilar insufficiency vertebrobasilar (VBIV) is a serious nerve disease and many old people suffer from it. Acupuncture has been widely applied in the treatment of VBIV. However, to our knowledge, there has been no systematic review or meta-analysis of randomized controlled trails regarding the effectiveness of this treatment. Here, we provide a protocol to evaluate the effectiveness and safety of acupuncture for VBIV.

METHODS

Relevant randomized controlled trials in 5 databases (EMBASE, PubMed, the Cochrane Central Register of Controlled Trials [Cochrane Library], Chinese Biomedical Literature Database [CBM], China National Knowledge Infrastructure [CNKI]) will be comprehensively searched by 2 researchers in December 2017. The clinical efficacy will be accepted as the primary outcomes. We will also use RevMan V.5.3 software to compute the data synthesis carefully when a meta-analysis is allowed.

RESULTS

This study will provide a high-quality synthesis of current evidence of acupuncture for VBIV from several aspects including clinical efficacy, the blood flow velocity of the left vertebral artery (LVA), the right vertebral artery (RVA), the basilar artery (BA)and adverse events.

CONCLUSION

The conclusion of our systematic review will provide evidence to judge whether acupuncture is an effective and safety intervention for patient with VBIV.

Combined Use of Intraoperative Indocyanine Green and Dynamic Angiography in Rotational Vertebral Artery Occlusion

Rotational vertebral artery occlusion (RVAO) is a well-documented surgically amenable cause of vertebrobasilar insufficiency. Traditionally, patients have been imaged using dynamic rotational angiography. We report a case of RVAO in which intraoperative indocyanine green angiography (ICGA) was used to confirm adequate surgical decompression of the VA. A 57-year-old female who presented with multiple episodes of syncope provoked by turning her head to the right. Rotational dynamic angiography revealed a dominant right VA that became occluded at the level of C5/6 with head rotation to the right. The patient underwent successful surgical decompression of the VA via an anterior cervical approach. ICGA demonstrated VA patency with head rotation. This was further confirmed by intraoperative dynamic catheter angiography. To the best of our knowledge, we present the first use of ICG combined with intra-operative dynamic rotational angiography to document the adequacy surgical decompression of the VA in a patient with RVAO.

Sleep problems and injury risk among juveniles: A systematic review and meta-analysis of observational studies

Recent studies have reported inconsistent results regarding the association between sleep problems and injury risk among juveniles. Moreover, the extent of this risk remains largely unexplored. Thus, a systematic review and meta-analysis was conducted by our team to determine whether sleep problems increase the incidence of injuries among juveniles. PubMed, PsycINFO, Embase, and Cochrane Library databases were searched for relevant studies that explored the association between sleep problems and injury risk and have been published before July 2016. Multivariate adjusted odds ratio (OR) and associated 95% confidence intervals (CIs) were extracted and pooled using random-effects models. A total of 10 observational studies involving 73,418 participants were identified. Meta-analysis findings suggested that juveniles with sleep problems held a 1.64 times higher risk of injury than that of juveniles without sleep problems (OR: 1.64, 95% CI: 1.44–1.85). This relationship was also supported by subgroup analyses, which were based on different countries and study designs. The current evidence indicates that sleep problems are significantly associated with injury risk among juveniles. Sleep problems are highly important for young people; hence, sleep researchers and occupational physicians should focus on this aspect. Nevertheless, high-quality and adequately powered observational studies are still needed.

Vasectomy and cardiovascular disease risk: A systematic review and meta-analysis

BACKGROUND

Even though several studies comparing vasectomy and cardiovascular disease (CVD) risk have been reported, most are small series with conflicting results. However, the extent of the risk is still uncertain. We therefore explored whether an association exists between vasectomy and CVD incidence and mortality.

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane Library databases for relevant studies published before January 2017. Multivariate adjusted odds ratio (OR) and associated 95% confidence intervals (CIs) and those by subgroups were extracted and pooled using random-effects models.

RESULTS

Overall, 12 observational studies (2 cross-sectional studies, 4 case-control studies, and 6 retrospective cohort studies) comprising 299,436 participants were identified. There was no statistically significant relationship between vasectomy and CVD risk (OR: 0.90, 95% CI: 0.81-1.00). Moreover, vasectomy was not associated with CVD mortality (OR: 0.90, 95% CI: 0.81-1.00), coronary heart disease (CHD) incidence (OR: 0.94, 95% CI: 0.88-1.01), stroke incidence (OR: 0.90, 95% CI: 0.72-1.13), and myocardial infarction (MI) incidence (OR: 0.95, 95% CI: 0.88-1.02), with no significant publication bias. In subgroup analyses, the findings on the association between vasectomy and CVD risk were consistent.

CONCLUSION

Our findings suggest that vasectomy is not associated with the excess risk of CVD incidence and mortality. Nevertheless, large-volume, well-designed observational studies, with different ethnic populations, low risk of bias, and adjusted confounding factors, are awaited to confirm and update the findings of this analysis.

Demographic aspects in cervical vertebral bodies' size and shape (C3-C7): a skeletal study

BACKGROUND CONTEXT

This cross-sectional study was conducted on the skeletal remains of individuals of known sex, age, and ethnic origin. The vertebral bodies of levels C3-C7 were measured and analyzed. Whereas many studies were performed on the size and shape of the vertebral bodies in the thoracic and lumbar spines, few have focused on the cervical vertebral bodies. Thus, there is insufficient data in the literature on the anatomy of the cervical spine, especially based on large study populations.

PURPOSE

To establish a large database on cervical vertebral bodies' size and shape and analyze their association with demographic parameters.

STUDY DESIGN

The population studied was composed of 277 individuals, adult males and females of African American (AA) and European American (EA) origin. The skeletal remains are housed at the Hamman-Todd Osteological collection (Cleveland Museum of Natural History, Cleveland, OH).

METHODS

A 3-D digitizer was used to measure the size and shape of the C3-C7 vertebral bodies. Descriptive statistics were carried out for all measurements. t Test and one-way analysis of variance were performed to assess differences in vertebral bodies' size and shape between different demographical groups (by age, sex, and ethnicity).

RESULTS

The vertebral bodies and foramina are significantly wider, more elongated, and higher in males compared to females. AA females and males manifest significantly greater vertebral bodies (width and length) in the upper and midcervical region (vertebrae C3-C5) than EA females and males. Nevertheless, the heights of the C3 and C4 vertebral bodies are significantly smaller among the AA population, regardless of sex. The vertebral foramina's width does not differ significantly between the two ethnic groups, independent of sex, whereas they tend to be elongated in the EA group (significant for C3, C5, C7). For most vertebrae, no significant differences were found in the superior facets' length between AA and EA males and females. Cervical vertebral bodies become wider and more elongated with age, although the changes in the latter dimension are much more pronounced than in the former. Notably, the body shape of the cervical vertebrae changes gradually from a more round shape (C3 length/width index=0.84) to a more oval one (C7 length/width index =0.65). This is due to the fact that the width dimensions increase by almost 40% from C3 to C7, whereas the length dimensions increase only by approximately 10%. Furthermore, there is a significant reduction in body height with age in C3-C6. In contrast, no significant changes in vertebral foramen size with age were found.

CONCLUSIONS

The cervical vertebral bodies' shape and size are sex-dependent phenomena, that is, in all parameters studied, the dimensions were greater in males than in females. For the midcervical level, there is a difference in body shape between individuals of different ethnic origins. The cervical vertebral bodies also exhibit considerable size and shape changes with age, that is, they become more elongated (oval shaped), wider, and shorter. In contrast, vertebral foramen size is age independent.

Duplex Ultrasonography-Detected Positional Vertebral Artery Occlusion in Upper Cervical Rheumatoid Arthritis

STUDY DESIGN

Prospective imaging study.

OBJECTIVE

To clarify the frequency of positional vertebral artery (VA) occlusion using duplex ultrasonography in patients with rheumatoid arthritis (RA).

SUMMARY OF BACKGROUND DATA

Some patients with upper cervical RA develop thromboembolic stroke related to positional and transient VA occlusions; however, whether RA patients have positional VA occlusion without neurological symptoms is unclear.

METHODS

Outpatients with RA were enrolled. Clinical data were collected, and radiograph examinations were performed to measure the anterior atlantodental interval (AADI), the posterior atlantodental interval (PADI), and the Ranawat method. Patients underwent duplex ultrasonography during rotation to the contralateral side of the examination side, flexion, and extension of their neck. If positional VA occlusion was detected, CT angiography was conducted in the neutral position and in the same position that showed VA occlusion on duplex ultrasonography. Clinical and radiological data were compared between the VA occlusion (VAO) group and the non-VAO group. Sensitivity-specificity curve analyses were performed to clarify optimal threshold values of AADI, PADI, and the Ranawat method for predicting positional VA occlusion.

RESULTS

Of the 132 RA patients, dynamic duplex ultrasonography showed positional VA occlusion in eight (6%) patients. Patients in the VAO group had a greater AADI (median, 7.4 vs. 2.3 mm; P < 0.001), a shorter PADI (median, 13.7 vs. 19.6 mm; P = 0.002), and a lower Ranawat value (median, 13.7 vs. 16.8 mm; P = 0.006) than those in the non-VAO group. Cut-off values of AADI, PADI, and the Ranawat method for predicting positional VA occlusion were 6.5, 14.0, and 15.5 mm, respectively.

CONCLUSION

A subset of RA patients developed positional VA occlusion associated with cervical spine involvement.

Bow hunter's syndrome revisited: 2 new cases and literature review of 124 cases

Rotational occlusion of the vertebral artery (VA), or bow hunter's syndrome, is a rare yet surgically treatable cause of vertebrobasilar insufficiency. The underlying pathology is dynamic stenosis of the VA by osteophytes, fibrous bands, or lateral disc herniation with neck rotation or extension. The authors present 2 previously unreported cases of bow hunter's syndrome and summarize 124 cases identified in a literature review. Both patients in the new cases were treated by VA decompression and fusion of the subaxial spine. Each had > 50% occlusion of the left VA at the point of entry into the transverse foramen with a contralateral VA that ended in the posterior inferior cerebellar artery. Analyzing data from 126 cases (the 2 new cases in addition to the previously published 124), the authors report that stenosis was noted within V1 in 4% of cases, in V2 in 58%, in V3 in 36%, and distal to C-1 in 2%. Patients presented in the 5th to 7th decade of life and were more often male than female. The stenotic area was decompressed in 85 (73%) of the 116 patients for whom the type of treatment was reported (V1, 4 [80%] of 5; V2, 52 [83%] of 63; V3/V4, 29 [60%] of 48). Less commonly, fusion or combined decompression and fusion was used (V2, 7 [11%] of 63; V3/V4, 14 [29%] of 48). Most patients reported complete resolution of symptoms. The authors conclude that patients with bow hunter's syndrome classically have an impaired collateral blood flow to the brainstem. This condition carries an excellent prognosis with decompression, fusion, or combined surgery, and individual patient characteristics should guide the choice of therapy.

Rotational vertebral artery occlusion secondary to adjacent-level degeneration following anterior cervical discectomy and fusion

Rotational vertebral artery occlusion (RVAO), or bow hunter's syndrome, most often occurs at the C1-2 level on physiological head rotation. It presents with symptoms of vertebrobasilar insufficiency (VBI). Several previously published studies have reported on subaxial sites of vertebral artery (VA) compression by head rotation. The authors report a case of subaxial spine RVAO due to adjacent-segment degeneration. A 52-year-old man presented with dizziness when rotating his head to the left. Twenty years earlier, he had undergone a C4-5 anterior cervical discectomy and fusion (ACDF) for a herniated disc. Imaging studies including a dynamic CT angiography and dynamic catheter angiography revealed occlusion of the left VA at the C3-4 level when the patient turned his head to the left, in the setting of an aberrant vertebrobasilar system. Successful treatment was achieved by surgical decompression of the left VA and C3-4 ACDF. Expedited diagnosis and treatment are dependent on the recognition of this unusual manifestation of RVAO, especially when patients present with nonspecific symptoms of VBI.

Simultaneous bilateral stenosis of the vertebral arteries treated by unilateral decompression: a case report

A 56-year-old man presented with a 3-month history of progressive dizziness. His dizziness was aggravated when his head was rotated to the right side. Diagnostic angiography showed that a normal right-sided vertebral artery in the neutral position became an abnormal vertebral artery with two stenotic lesions at the C3-4 and C5-6 levels when the patient's head was turned to the right. A normal left-sided vertebral artery also showed a stenotic lesion at the C2 level when the patient's head was turned right. The axial dimensions of the bilateral vertebral arteries were similar. The patient was successfully treated with decompression of only one level (C5-6). We conclude that if a bilateral stenosis is found upon one directional head rotation and the bilateral vertebral arteries are similarly sized, a one-sided treatment may suffice.

Bow hunter's syndrome causing vertebrobasilar insufficiency in a young man with neck muscle hypertrophy

Vertebrobasilar insufficiency is characterized by impaired blood flow within the posterior circulation, producing symptoms of vertigo, nausea, vomiting, visual disturbances, and syncope. Given these nonspecific symptoms, the diagnosis of vertebrobasilar ischemia may be difficult to distinguish from more benign conditions. A healthy 37-year-old man presented to our clinic with near syncope upon turning his head to the left. Dynamic angiography revealed occlusion of the left vertebral artery at C7 with 90° head rotation to the left, consistent with bow hunter's syndrome. No obvious bony abnormalities were identified on computed tomography or magnetic resonance imaging scans. Transient rotational vertebral artery syndrome, a rare cause of vertebrobasilar insufficiency, has most often been reported at the C1-2 level, and the majority of cases occur in patients >50 years of age because of degenerative osteophytes and contralateral atherosclerosis. We present the unusual case of a young man with symptoms of vertebrobasilar insufficiency and discuss the potential effects of weightlifting and neck muscle hypertrophy on vertebral artery flow dynamics.

The diagnosis of vertebrobasilar insufficiency using transcranial Doppler ultrasound

Background. Vertebrobasilar insufficiency (VBI) is a hemodynamic posterior circulation transient ischemic attack (TIA) caused by intermittent vertebral artery occlusion that is induced by a head rotation or extension. VBI may result from large vessel atherosclerotic disease, dissection, cervical compressive lesions, and subclavian steal phenomenon. Diagnostic transcranial Doppler (TCD) of VBI disease and hemodynamic posterior circulation TCD monitoring in symptomatic positions might prove a useful tool in establishing the diagnosis. Patient and Material/Method. A 50-year-old Caucasian man presented with a one-year history of episodic positional vertigo and ataxic gait that were induced by a neck extension and resolved by an upright position or a neck flexion. Computed tomography angiogram (CTA) and TCD confirmed the presence of VBI where no blood flow was detected through posterior cerebral arteries in the symptomatic position (head extension position). Conclusion. TCD is a promising noninvasive technique that might have a role as a diagnostic test in VBI.

Bowhunter's syndrome diagnosed with provocative digital subtraction cerebral angiography

Bowhunter's syndrome, also known as rotational occlusion of the vertebral artery, involves posterior circulation ischemia resulting from dynamic compromise of the dominant vertebral artery. This case highlights the importance of provocative digital subtraction angiography in making the diagnosis. A 41-year-old man presented for outpatient neurological evaluation for "lightheadedness" of several years' duration provoked by leftward head rotation. The only abnormality identified on initial magnetic resonance angiography was atresia of the nondominant left vertebral artery. Conventional digital subtraction angiography (DSA) followed by provocative DSA revealed development of a dynamic stenosis of the right vertebral artery involving the extraforaminal segment just superior to the C1 vertebra. Noncontrast computed tomography of the cervical spine confirmed ossification of the posterior right atlanto-occipital membrane leading to a near complete bony arcuate foramen. Following neurosurgical decompression, the patient demonstrated complete resolution of all neurologic symptoms. Bowhunter's syndrome is a unique clinical entity that must be considered in the evaluation of patients with symptoms of posterior circulation ischemia. Provocative DSA remains the preferred modality for definitive diagnosis.

Rare case of bilateral vertebral artery stenosis caused by C4-5 spondylotic changes manifesting with bilateral bow hunter's syndrome

BACKGROUND

Rotational vertebral artery occlusion syndrome refers to vertebrobasilar insufficiency as a result of mechanical occlusion or stenosis of the vertebral artery by head rotation. In most cases, symptoms are produced on extension or rotation to one side. No case of bow hunter's syndrome with bilateral presentation at the C4 level has yet been reported.

CASE DESCRIPTION

A 54-year-old man presented with symptomatic bilateral bow hunter's syndrome induced by head rotation. The patient complained of intermittent dizziness, episodes of double vision, nonpulsatile tinnitus, and headaches indicative of vertebral artery insufficiency with exacerbation of symptoms on rotation of his head to either side. Computed tomography angiography showed bilateral vertebral artery stenosis, and dynamic cerebral angiography revealed bilateral rotational vertebral artery occlusion, with compression of the ipsilateral vertebral artery on head rotation to either side. Bilateral surgical decompression at C4-5 with anterior cervical diskectomy and fusion with a plate was performed.

CONCLUSIONS

Bony obstruction of the vertebral artery on head rotation tends to occur at levels C4 and below, affecting the ipsilateral side. In this rare case, symptomatic bilateral vertebral artery stenosis occurred as a result of bony compression and was symptomatic on head rotation both to the right and to the left. This stenosis was improved with anterior decompression bilaterally, and no further events occurred postoperatively.

Bow-hunter's syndrome caused by dynamic vertebral artery stenosis at the cranio-cervical junction--a management algorithm based on a systematic review and a clinical series

Bow hunter's syndrome (BHS) is defined as symptomatic, vertebro-basilar insufficiency caused by mechanical occlusion of the vertebral artery (VA) at the atlanto-axial level during head rotation. In the literature, about 40 cases have been reported. However, due to the rarity of this pathology, there are no guidelines for diagnosis and treatment. Conservative, surgical, and endovascular concepts have been proposed. In order to work out an algorithm, we performed a systematic review of the literature and a retrospective analysis of patients, which have been treated in our institutions over the last decade. The clinical series was comprised of five patients. The symptoms ranged from transient vertigo to posterior circulation stroke. Diagnosis was established by dynamic angiography. In all patients, the VA was decompressed; one patient required additional fusion. The clinical and radiological results were good, and the treatment-related morbidity was low. The literature review demonstrated that Bow hunter's syndrome is a rare pathology but associated with a pathognomonic and serious clinical presentation. The gold standard of diagnosis is dynamic angiography, and patients were well managed with tailored vertebral artery decompression. By this management, clinical and radiological results were excellent and the treatment-related morbidity was low.

Rotational vertebral artery occlusion-series of 9 cases

BACKGROUND

Rotational vertebral artery syndrome (RVAS) is a rare entity about which previously published studies are mostly limited to individual case reports.

OBJECTIVE

To report our decade-long experience with this syndrome in 9 patients with compression ranging from the occiput to C6.

METHODS

We utilized a posterior approach for lesions rostral to C4 and an anterior approach for lesions at or caudal to C4. Furthermore, we demonstrated the feasibility and efficacy of a minimally invasive posterior cervical approach. Patient profile, operative indications, surgical approach, operative findings, complications, and long-term follow-up were reviewed and discussed.

RESULTS

Average follow-up was 47 months. All procedures provided excellent outcomes by Glasgow Outcome Scale scores. The anterior approach had significantly less blood loss (187.5 mL vs 450 mL, P = .00016) and shorter hospitalization length (2 days vs 4.5 days; P = .0001) compared with the far-lateral approach. There was one complication of cervical instability in the far-lateral approach cohort. As an alternative to the far-lateral surgery, a minimally invasive approach resulted in shorter hospitalization (2 days) and less blood loss (10 mL) while avoiding the complication of cervical instability.

CONCLUSION

We demonstrated the safety, efficacy, and durability of 3 surgical approaches for RVAS. Proper examination, preoperative imaging, and surgical planning were necessary for a satisfactory outcome.

Bow Hunter's Stroke Caused by a Severe Facet Hypertrophy of C1-2

Bow hunter's stroke is a rare symptomatic vertebrobasilar insufficiency in which vertebral artery (VA) is mechanically occluded during head rotation. Various pathologic conditions have been reported as causes of bow hunter's stroke. However, bow hunter's stroke caused by facet hypertrophy of C1-2 has not been reported. A 71-year-old woman presented with symptoms of vertebrobasilar insufficiency. Spine computed tomography showed massive facet hypertrophy on the left side of C1-2 level. A VA angiogram with her head rotated to the right revealed significant stenosis of left VA. C1-2 posterior fixation and fusion was performed to prevent serious neurologic deficit from vertebrobasilar stroke.

Minimally invasive decompression of a suboccipital osseous prominence causing rotational vertebral artery occlusion. Case report

Surgical decompression of the vertebral artery (VA) between the suboccipital area and C-1 is typically performed via a large midline incision or a far-lateral approach. Such traditional open approaches are often associated with significant muscle dissection and blood loss. In this case, a 12-year-old boy suffered a stroke related to a VA rotational occlusion (bow hunter syndrome) and dissection due to a prominent suboccipital bone mass. Successful decompression of the VA was performed via a minimally invasive 22-mm tubular retractor. This is the first reported case report of a minimally invasive decompression of the VA between the skull base and C-1.

Subaxial positional vertebral artery occlusion corrected by decompression and fusion

STUDY DESIGN

A rare case of subaxial vertebral artery (VA) positional occlusion is reviewed and treatment methods discussed.

OBJECTIVE

The decision process involved in treating subaxial VA positional occlusion is reviewed.

SUMMARY OF BACKGROUND DATA

Bow Hunter stroke is a symptomatic vertebrobasilar insufficiency caused by stenosis or occlusion of the VA with physiologic head rotation. It most commonly occurs at the junction of C1 and C2 and less commonly as the VA enters the C6 transverse foramen. Rotational stenosis of the VA is quite rare during its passage through the foramen transversarium of C3-C6.

METHODS

A 48-year-old gentleman presented describing syncopal episodes when he turns his head to the left side. Imaging revealed a congenitally narrowed right foramen transversarium and high-grade stenosis of the left VA when the head was turned to the left. A routine anterior cervical discectomy and fusion was performed with the addition of decompression of the left transverse foramen.

RESULTS

Vascular imaging should be performed with the patient's head in both the neutral position and in the symptomatic position. Surgical treatment may be chosen if conservative therapies fail and generally has 1 of 2 goals-decompression of the VA or elimination of rotational movement at the affected level. Decisions between anterior and posterior decompressions may be influenced by the surgeon's comfort level with the approach and if the transverse foramen stenosis is caused mainly by an anterior (osteophytes at the uncinate process) or posterior (facet joint hypertrophy) process. The patient remains symptom-free after treatment.

CONCLUSION

This report demonstrates the condition in the subaxial spine and describes successful treatment by fusion of the affected level combined with decompression of the foramen transversarium-a combination of previously described therapies.

Simultaneous bilateral vertebral artery occlusion in the lower cervical spine manifesting as bow hunter's syndrome

A 59-year-old male had suffered near-syncopal episodes for more than one year that occurred immediately on turning his head to the left. Cerebral magnetic resonance (MR) imaging did not detect any contributing lesions with well-developed posterior communicating arteries. Dynamic radiography of the cervical spine showed mild instability at C5-6 and concomitant intramedullary hyperintensity confirmed by T(2)-weighted MR imaging. Cervical computed tomography demonstrated an osseous protrusion in the right foramen transversarium at C5. Dynamic cerebral angiography revealed simultaneous vertebral artery (VA) occlusion at C6 on the right and C5 on the left associated with leftward head rotation. The VA showed an intact course at the C1 to C2 levels. The patient underwent anterior fusion followed by decompressive foraminotomy at C5-6 and C6-7 and meticulous resection of the markedly thickened fibroligamentous structure which was considered to contribute to the rotational VA occlusion. Postoperatively he no longer suffered near-syncope during head rotation. Bow hunter's syndrome is an infrequent type of vertebrobasilar insufficiency that may need surgical management for potential threat of ischemic stroke. Simultaneous VA occlusion at the lower cervical level can cause bow hunter's syndrome. Dynamic cerebral angiography is a useful modality for evaluating bow hunter's syndrome even if the patient cannot tolerate dynamic examination for the immediate symptom. Accurate anatomical knowledge of the uncovertebral foraminal region combined with intraoperative dynamic study is essential for safe surgery to the VA and favorable outcome.

Vertebral artery decompression in a patient with rotational occlusion

We report a patient who suffered drop attacks during head reclination. Computer tomography of the cervical spine demonstrated a stenotic right vertebral artery at C4/5. However, Doppler ultrasonography of the vertebral artery showed no abnormality. Angiography confirmed complete occlusion of the left vertebral and a stenosis of the right vertebral artery. Dynamic angiography indicated occlusion of the stenotic region on the right side during reclination of the head. Surgery using a posterior approach with decompression of the vertebral artery, lead to an excellent outcome and the patient left the hospital without any symptoms. Therefore, in patients with drop attacks and normal ultrasonography, a stenosis of the vertebral artery caused by a spondylophytic compression could still be the cause. At worst, the stenosis could lead to brain infarction if left untreated. Dynamic angiography is crucial for the diagnosis and surgical decompression has excellent results.

Anterior vertebral artery decompression with an ultrasonic bone curette to treat bow hunter's syndrome

We report a patient with bow hunter's syndrome who was treated by anterior decompression of the vertebral artery (VA) using an ultrasonic bone curette (SONOPET). This 60-year-old man reported almost losing consciousness upon head rotation. Although the right VA appeared normal at the natural head position, upon left head rotation it became completely occluded at the transverse foramen of C2. We performed anterior decompression of the right VA at the axis using a high-speed drill and SONOPET. For anterior decompression of the VA in a deep and narrow operative field, we recommend use of SONOPET, which permits safe, easy bone dissection.

Intraoperative dynamic angiography to detect resolution of Bow Hunter's syndrome: Technical case report

BACKGROUND

Bow Hunter's syndrome is a rare form of vertebrobasilar insufficiency that may be successfully treated by surgical intervention. Use of intraoperative dynamic transcranial Doppler ultrasound for surgical treatment of vertebrobasilar insufficiency has been described in literature. However, this technique was inconsistent and unreliable in some patients. We present a case of a patient with Bow Hunter's syndrome treated surgically and emphasize the valuable addition of intraoperative dynamic angiography to determine resolution of vertebral artery compromise.

CASE DESCRIPTION

The patient was a 58-year-old man with complaints of dizziness, vertigo, and near-syncopal episodes that occurred when he rotated his head to the left. Imaging revealed compromise of the dominant left vertebral artery with leftward head rotation. An anterior cervical approach with decompression of the left subaxial vertebral artery was performed. Significant osteophyte formation was observed. Removal of bone and decompression of the vertebral artery was performed. Intraoperative dynamic angiography confirmed resolution of vertebral artery compression and minimized the amount of decompression. No further intervention was required.

CONCLUSION

Intraoperative dynamic angiography is a definitive test to determine hemodynamic resolution of Bow Hunter's syndrome. It offers real-time feedback of vertebral artery decompression, potentially minimizes the amount of decompression, and can be performed safely.

Rotational vertebrobasilar ischemia: hemodynamic assessment and surgical treatment

OBJECTIVE

Rotational vertebrobasilar insufficiency is a severe and incapacitating condition. Proper investigation and management are essential to reestablish normal posterior circulation hemodynamics, improve symptoms, and prevent stroke. We present a series of 10 patients with rotational vertebrobasilar ischemia who were treated surgically and emphasize the importance of transcranial Doppler in the diagnosis and management of this condition.

METHODS

All patients presented with symptoms of vertebrobasilar insufficiency induced by head turning. Transcranial Doppler documented a significant decrease in the posterior cerebral artery velocities during head turning that correlated with the symptoms in all patients. A dynamic cerebral angiogram was performed to demonstrate the site and extent of vertebral artery compression.

RESULTS

The surgical technique performed was tailored to each individual patient on the basis of the anatomic location, pathogenesis, and mechanism of the vertebral artery compression. Five patients underwent removal of osteophytes at the level of the subaxial cervical spine, one patient had a discectomy, two patients had a decompression only at the level of C1-C2, and two patients had a decompression and fusion at the C1-C2 level.

CONCLUSION

The transcranial Doppler is extremely useful to document the altered hemodynamics preoperatively and verify the return of normal posterior circulation velocities after the surgical decompression in patients with rotational vertebrobasilar ischemia. Surgical treatment is very effective, and excellent long-term results can be expected in the vast majority of patients after decompression of the vertebral artery.

Have cranio-vertebral junction anomalies been overlooked as a cause of vertebro-basilar insufficiency?

STUDY DESIGN

A prospective controlled study using single photon emission computed tomography (SPECT) to assess cerebellar perfusion in a cohort of 19 patients with congenital cranio-vertebral junction (CVJ) anomalies, with or without vertebro-basilar insufficiency (VBI).

OBJECTIVE

To correlate symptoms of VBI with the presence of posterior circulation ischemia in patients with congenital CVJ anomalies, using technetium 99m ethylene cystine dimer SPECT.

SUMMARY OF BACKGROUND DATA

Patients with VBI are rarely investigated for CVJ anomalies, despite the fact that a significant number of patients with congenital CVJ anomalies has VBI. There are also no studies quantifying outcome of surgical interventions, such as like occipito-cervical fusion, in patients with VBI and CVJ anomalies.

METHODS

There were 19 consecutive patients with congenital CVJ anomalies who were scheduled for combined transoral odontoidectomy and occipito-cervical fusion were included in the study. Technetium 99m ethylene cystine dimer brain SPECT and clinical assessment of all patients was performed in the preoperative period and at 4 weeks after surgery. Before surgery, patients were divided into 2 groups depending on the clinical findings: (1) symptomatic group, consisting of 12 patients having features suggestive of VBI (drop attacks, episodic vertigo, visual disturbances and dysarthria); and (2) control group, consisting of 7 patients without symptoms of VBI.

RESULTS

SPECT showed decreased cerebellar perfusion in 75% (n = 9) of patients in the symptomatic group compared to 14% (n = 1) in the control group before surgery (Fisher exact 2-tailed test, P = 0.019). Following surgery, 8 patients (88.9%) in the symptomatic group and none in the control group had improvement in cerebellar perfusion. Two patients in the symptomatic group who had meningitis develop during the postoperative period had a decrease in cerebellar perfusion on follow-up SPECT. Clinically, all patients with improvement in cerebellar perfusion had improvement in the symptoms of VBI at 1 month of follow-up.

CONCLUSIONS

A significant number of patients with congenital CVJ anomalies who have symptoms of VBI develop have decreased cerebellar perfusion shown by SPECT. Rigid internal fixation of the CVJ may alleviate symptoms and improve posterior circulation in some of these patients.

Defining the Effect of Cervical Manipulation on Vertebral Artery Integrity: Establishment of an Animal Model

BACKGROUND

Cervical spine manipulation is most often performed to affect relief of musculoskeletal complaints of the head and neck. Performed typically without complication, this modality is thought to be a potential cause of cerebrovascular injury, although a cause-effect relation has yet to be established. To explore this relation, an experimental platform is needed that is accessible and biologically responsive.

OBJECTIVE

To establish an animal model capable of accommodating (1) direct study of its vertebral arteries and (2) creation of controlled interventions simulating arterial injury.

STUDY DESIGN

Descriptive.

METHODS

Under fluoroscopic guidance, an ultrasonic catheter was inserted into the left vertebral artery of 3 anesthetized dogs. The ultrasonic probe was then drawn proximally through the artery at a specific rate, and cross-sectional images of the vessel were collected. These images were then reconstructed to provide a variety of 2- and 3-dimensional representations of the vessel. This procedure was repeated after the overinflation and/or displacement of an angiographic balloon within the vertebral artery itself.

RESULTS

The resulting ultrasonic images were able to delineate the structural layers that constitute the vertebral artery. Analysis of 2- and 3-dimensional reconstructions before and after angiographic intervention revealed the creation of discrete vascular injuries (aneurysm or dissection).

CONCLUSIONS

For the first time, an animal model has been established that permits direct interrogation of the internal structures of the vertebral artery. This model can also be manipulated to create "preexisting" vascular injuries that are thought to be possible prerequisites for cerebrovascular injury associated with manipulation. As a result, an experimental platform has been established that is capable of providing investigators of all backgrounds with the ability to quantify biologic and mechanical outcomes of cervical manipulation.

Transient rotational compression of the vertebral artery caused by herniated cervical disc. Case report

Of the many causes of vertebrobasilar insufficiency (VBI), extrinsic compression of the vertebral artery (VA) is relatively uncommon. A syndrome of VBI caused by extrinsic compression of the VA secondary to head rotation has been termed positional vertebrobasilar ischemia. The authors present a case of transient VBI caused by herniation of a cervical disc. Transcranial Doppler ultrasonography was used preoperatively to confirm the diagnosis and intraoperatively to monitor cerebral perfusion and to confirm that adequate decompression of the VA had been achieved.

Bow hunter's syndrome in the setting of contralateral vertebral artery stenosis: evaluation and treatment options

STUDY DESIGN

A case report.

OBJECTIVE

To illustrate a rare case of bow hunter's syndrome in a patient with significant contralateral vertebral artery (VA) occlusive disease.

SUMMARY OF BACKGROUND DATA

Bow hunter's syndrome is an uncommon condition in which the VA is symptomatically occluded during neck rotation. This case is interesting in that the patient had what appeared to be a normal right VA and occluded left VA when the head was in the neutral position. When the head was rotated 45 degrees to the left, the patient's right VA was occluded (bow hunter's finding), and it became apparent that the left VA was not completely occluded (as it appeared in the neutral position angiogram) but rather was 90% stenosed. The complete occlusion appearance in the neutral position was an angiographic phenomenon caused by competitive flow through the open right VA. When the patient rotated his head to the left, he occluded his right VA and had insufficient blood flow through the left VA, thus creating a symptomatic ischemic state.

METHODS

This case was studied using dynamic computed tomography imaging, single-photon emission computed tomography, transcranial Doppler ultrasound, brain stem auditory evoked potentials, and dynamic range-of-motion cerebral angiography.

RESULTS

The patient demonstrated bow hunter's syndrome as documented on clinical examination and history. Transcranial Doppler studies, dynamic computed tomography scanning, and cerebral/cervical angiography confirmed the diagnosis and revealed an interesting angiographic pattern, which explained the patient's symptoms and findings only when angiographic flow patterns were taken into consideration.

CONCLUSIONS

Bow hunter's syndrome should be suspected when a patient presents with reproducible vertebrobasilar symptoms on rotating the neck. Quantitative documentation using imaging and electroneurophysiologic tests is important when assessing this subjective process. Careful evaluation of the angiographic imagescan often help explain an odd flow pattern and provide the physician with a range of treatment options.

Anterior decompression of the atlantoaxial vertebral artery to treat bow hunter's stroke: technical case report

OBJECTIVE AND IMPORTANCE

Bow hunter's stroke is a symptomatic vertebrobasilar insufficiency caused by stenosis or occlusion of the vertebral artery at the C1C2 level with head rotation. No case of anterior decompression of the vertebral artery for surgical treatment of bow hunter's stroke has been reported.

CLINICAL PRESENTATION

A 47-year-old male patient presented with repeated episodes of unconsciousness caused by turning his head approximately 40 degrees to the right; he recovered consciousness within approximately 10 seconds after his head was returned to the neutral position. Angiography revealed an occluded right vertebral artery and temporary occlusion of the left vertebral artery, at the level of the C2 transverse foramen, when the patient's head was turned approximately 40 degrees to the right.

INTERVENTION

Anterior decompression of the left vertebral artery at the transverse foramen of the axis was performed. Postoperative angiography demonstrated sufficient flow in the left vertebral artery even when the neck was rotated.

CONCLUSION

The patient was discharged without neurological deficits. We demonstrate that simple surgical untethering of the vertebral artery at the transverse foramen of the axis is an effective method of treatment that avoids the limitation of head rotation. The advantage of this procedure is that it does not result in postoperative restriction of the patient's neck movements. The anterior approach, with decompression of the transverse foramen of the axis, in the present case provided adequate exposure of the vertebral artery and resulted in a satisfactory outcome.

Inflatable pillows as axillary support devices during surgery performed in the lateral decubitus position under epidural anesthesia

The lateral decubitus position can cause dependent shoulder discomfort or result in traction on the brachial plexus. We measured pressure beneath the dependent shoulder and lateral angulation of the cervical spine in patients positioned in the lateral decubitus position for total hip replacement under epidural anesthesia. Inflatable pillows (Shoulder-Float) beneath the chest wall and head reduced pressure beneath the dependent shoulder from 66 to 12 mm Hg (P < 0.001) and lateral angulation of the cervical spine from 14 degrees to 4 degrees (P < 0.001). In a randomized crossover study of a further 15 patients, the use of inflatable pillows resulted in significantly less pressure beneath the dependent shoulder and chest wall than either a gel-pad or a 1000-mL lactated Ringer's bag. Inflatable pillows placed beneath the chest wall and head in the lateral decubitus position provided lower pressure beneath the dependent shoulder than other support devices and facilitated alignment of the cervical spine.

IMPLICATIONS

When patients lie on their side, this results in pressure beneath the shoulder and tilting of the head and neck to one side. These problems were effectively corrected with an inflatable pillow (Shoulder-Float).

Bow Hunter's stroke caused by a nondominant vertebral artery occlusion: case report

OBJECTIVE AND IMPORTANCE

Bow hunter's stroke is a consequence of vertebrobasilar insufficiency as a result of mechanical occlusion or stenosis of the vertebral artery at the C1-C2 level by head rotation. In most cases, a dominant vertebral artery is involved. No case of bow hunter's stroke as a result of mechanical occlusion of a nondominant vertebral artery has ever been reported.

CLINICAL PRESENTATION

We describe a rare case of Wallenberg's syndrome caused by occlusion of a nondominant vertebral artery induced by head rotation. The patient complained of vertigo and paresthesia of the left face and the right extremities when he rotated his head 45 degrees or more to the right.

INTERVENTION

Dynamic angiography revealed that the left vertebral artery was smaller than the right, terminated in a branch of the posteroinferior cerebellar artery, and was stretched and completely occluded at the C1-C2 level with the head rotated 45 degrees to the right. The right vertebral artery was normal when the head was rotated to either the right or the left. Three-dimensional enhanced computed tomography with the head rotated 45 degrees to the right revealed that the left vertebral artery was stretched and occluded by dislodgment between C1 and C2. Cerebral blood flow scintigraphy with head rotation demonstrated that blood flow was decreased in the lower portion of the left cerebellar hemisphere. C1-C2 posterior fixation was performed to prevent life-threatening neurological accidents.

CONCLUSION

We emphasize that the diagnosis of bow hunter's stroke should be based not only on angiographic findings but also on hemodynamic studies with head rotation.

Rotational occlusion of the vertebral artery caused by transverse process hyperrotation and unilateral apophyseal joint subluxation. Case report

The authors describe transverse process hyperrotation and unilateral apophyseal joint subluxation as a novel mechanism of rotational vertebral artery (VA) occlusion. The patient, a 56-year-old man, complained of episodic bilateral blindness when rotating his head more than 90 degrees to the right. Plain cervical x-ray films showed spondylotic osteophytes of the right C4-5 uncovertebral portion. Dynamic angiography revealed right VA occlusion at C4-5 and left VA occlusion at C1-2 with head rotation to the right. It was demonstrated on three-dimensional images constructed from computerized tomography scans that C-4 transverse process hyperrotation compressed the right VA against the apex of the C-5 subluxating superior articular process via the inner surface of the transverse process anterior root (processus costarius) rather than the osteophytes. It is also proposed that the true site of occlusion is different from that observed in angiographic studies.

Comparison of C1-2 posterior fusion and decompression of the vertebral artery in the treatment of bow hunter's stroke

Bow hunter's stroke results from vertebrobasilar insufficiency caused by mechanical occlusion or stenosis of the vertebral artery (VA) at the C1-2 level on head rotation. Surgical treatment of this condition may be chosen to avoid life-threatening accidents or because patients complain that conservative treatments such as verbal warnings or use of a neck brace to limit head and neck rotation are ineffective and thus restrict their lifestyle. Posterior fusion involving C1-2 has long been used to limit atlantoaxial rotational movements. However, it has the serious disadvantage that the range of head motion is severely reduced. Recently, decompression of the atlantoaxial portions of the affected VA has been used because it does not limit physiological neck movements. However, no long-term follow-up review of patients who have undergone this procedure has been conducted, and it is unclear whether this procedure always provides relief of symptoms. To answer this question, the results of C1-2 posterior fusion were compared with decompression of the VA for the treatment of bow hunter's stroke.