Is Kambin's Triangle Safe or Not for Percutaneous Endoscopic Transforaminal Oblique Fixation from the Posterior Corner in the Lumbar Spine: A Neuroimaging Anatomic Assessment.

BACKGROUND: Nerve root injury and dural tears are important complications in endoscopic spine techniques. Whether Kambin's triangle is safe or not is unknown for percutaneous endoscopic transforaminal oblique fixation from the posterior corner (PETOFPC) in lumbar spine. This study aimed to verify neural safety of PETOFPC and to define and evaluate the ideal operating target and actual safe working area in Kambin's triangle for PETOFPC. METHODS: Lumbar magnetic resonance imaging was performed in 60 outpatients. The distances from the working targets to exiting nerve roots and dural sac/traversing nerve roots in the coronal and sagittal planes (c1-c6, s1-s6) and the distances from the exiting roots to the dural sac/traversing nerve roots in the upper and lower endplate planes (d1 and d2) were measured and statistically analyzed. RESULTS: All coronal planes (c1-c6) first increased and then decreased; they gradually increased from L1-2, maximized in L4-5, and decreased slightly in L5-S1. In L1-2 through L5-S1, d1 and d2 gradually increased (F = 249.7, P < 0.0001; F = 511.7, P < 0.0001), d2 > d1 (P < 0.05). Values of d1 and d2 were smallest in L1-2 (6.71 ± 2.10 mm and 11.89 ± 2.55 mm) and largest in L5-S1 (13.37 ± 4.09 mm and 22.05 ± 3.96 mm). With the outward shift of the targets in the sagittal plane, both s1, s3, s5 and s2, s4, s6 gradually decreased (s1 > s3 > s5, s2 > s4 > s6). CONCLUSIONS: We calculated the ideal operating target and actual safe area and further proved that Kambin's triangle is safe enough for PETOFPC. PETOFPC is a promising technology and may have great clinical significance.

Diagnostic performance of diffusion-weighted MR neurography as an adjunct to conventional MRI for the assessment of brachial plexus pathology.

OBJECTIVE: To investigate the diagnostic performance of diffusion-weighted (DW) MR neurography as an adjunct to conventional MRI for the assessment of brachial plexus pathology. METHODS: DW MR neurography scans (short tau inversion recovery fat suppression and b-value of 800 s/mm2) of 15 consecutive patients with and 45 randomly selected patients without brachial plexus abnormalities were independently and blindly reviewed by a 5th year radiology resident, a junior neuroradiologist, and a senior neuroradiologist. RESULTS: Median interpretation times ranged between 20 and 30 s. Interobserver agreement was substantial (κ coefficients of 0.715-0.739). For the 5th year radiology resident, sensitivity was 53.3% (95% CI, 30.1-75.2%) and specificity was 100% (95% CI, 92.1-100%). For the junior neuroradiologist, sensitivity was 66.7% (95% CI, 41.7-84.8%) and specificity was 100% (95% CI, 92.1-100%). For the senior neuroradiologist, sensitivity was 73.3% (95% CI, 48.1-89.1%) and specificity was 95.6% (95% CI, 85.2-98.8%). Traumatic injury, metastases, radiation-induced plexopathy, schwannoma, and inflammatory process of unknown cause could be detected by the majority of readers (100% detection rate for each disease entity by at least two readers). Neuralgic amyotrophy, iatrogenic injury after first rib resection, and cervical disc herniation causing root compression were not detected by the majority of readers (0% detection rate for each disease entity by at least two readers). CONCLUSION: DW MR neurography may be a useful adjunct when assessing for brachial plexus abnormalities, because interpretation time is relatively short and the majority of abnormalities can be detected. KEY POINTS: • DW MR neurography interpretation time of the brachial plexus is relatively short (median interpretation times of 20 to 30 s). • Interobserver agreement between three readers with different levels of experience is substantial (κ coefficients of 0.715 to 0.739). • DW MR neurography can detect brachial plexus abnormalities with moderate sensitivity (53.3 to 73.3%) and high specificity (95.6 to 100%).

A national snapshot of the impact of clinical depression on post-surgical pain and adverse outcomes after anterior cervical discectomy and fusion for cervical myelopathy and radiculopathy: 10-year results from the US Nationwide Inpatient Sample.

Depression is associated with poorer outcomes in a wide spectrum of surgeries but the specific effects of depression in patients undergoing cervical spine surgery are unknown. This study aimed to evaluate the prevalence and impact of pre-surgical clinical depression on pain and other outcomes after surgery for cervical degenerative disc disease using a national representative database. Data of patients with cervical myelopathy and radiculopathy were extracted from the 2005-2014 US Nationwide Inpatient Sample (NIS) database. Included patients underwent anterior discectomy and fusion (ACDF). Acute or chronic post-surgical pain, postoperative complications, unfavorable discharge, length of stay (LOS) and hospital costs were evaluated. Totally 215,684 patients were included. Pre-surgical depression was found in 29,889 (13.86%) patients, with a prevalence nearly doubled during 2005-2014 in the US. Depression was independently associated with acute or chronic post-surgical pain (aOR: 1.432), unfavorable discharge (aOR: 1.311), prolonged LOS (aOR: 1.152), any complication (aOR: 1.232), respiratory complications/pneumonia (aOR: 1.153), dysphagia (aOR: 1.105), bleeding (aOR: 1.085), infection/sepsis (aOR: 1.529), and higher hospital costs (beta: 1080.640) compared to non-depression. No significant risk of delirium or venous thrombotic events was observed in patients with depression as compared to non-depression. Among patients receiving primary surgery, depression was independently associated with prolonged LOS (aOR: 1.150), any complication (aOR:1.233) and postoperative pain (aOR:1.927). In revision surgery, no significant associations were found for prolonged LOS, any complication or pain. In conclusion, in the US patients undergoing ACDF, pre-surgical clinical depression predicts post-surgical acute or chronic pain, a slightly prolonged LOS and the presence of any complication. Awareness of these associations may help clinicians stratify risk preoperatively and optimize patient care.

Ultrasonography has a diagnostic value in the assessment of cervical radiculopathy: A prospective pilot study.

OBJECTIVE: This study investigated the diagnostic accuracy of the difference in the cross-sectional areas (CSAs) of affected cervical nerve roots (NRs) for diagnosing cervical radiculopathy (CR). METHODS: In total, 102 CR patients and 219 healthy volunteers were examined with ultrasound. The CSA of the cervical NR at each level was measured on the affected side and the contralateral side in CR patients by blinded ultrasonographic technicians. The difference between the CSAs of CR patients and normal volunteers and the difference in the laterality of CSA at the same affected level (ΔCSA) were calculated for each cervical level. RESULTS: The CSAs of the affected NRs in CR patients were significantly larger than those of the unaffected NRs in CR patients and those of the control group at the C5, C6 and C7 levels (P<0.005). ΔCSA was also significantly larger in the CR group at all levels (P<0.001). A receiver operating characteristic analysis demonstrated that the threshold values were 9.6 mm2 (CSA) for C5NR and 15 mm2 for both C6NR and C7NR. CONCLUSIONS: This study revealed that the CSAs of affected NRs were enlarged and that the laterality of the CSA (ΔCSA) was greater in CR patients than in control patients. KEY POINTS: • Cervical radiculopathy is diagnosed through ultrasonographic measurement of the CSAs. • The CSAs of affected nerve roots were significantly enlarged. • The ΔCSA in the CR group was significantly higher than in the control group. • Diagnostic CSA and ΔCSA thresholds were identified.

Influence of preoperative nucleus pulposus status and radiculopathy on outcomes in mono-segmental lumbar total disc replacement: results from a nationwide registry.

BACKGROUND: Currently, herniated nucleus pulposus (HNP) with radiculopathy and other preconditions are regarded as relative or absolute contraindications for lumbar total disc replacement (TDR). In Switzerland it is left to the surgeon's discretion when to operate. The present study is based on the dataset of SWISSspine, a governmentally mandated health technology assessment registry. We hypothesized that preoperative nucleus pulposus status and presence or absence of radiculopathy has an influence on clinical outcomes in patients treated with mono-segmental lumbar TDR. METHODS: Between March 2005 and April 2009, 416 patients underwent mono-segmental lumbar TDR, which was documented in a prospective observational multicenter mode. The data collection consisted of perioperative and follow-up data (physician based) and clinical outcomes (NASS, EQ-5D).Patients were divided into four groups according to their preoperative status: 1) group degenerative disc disease ("DDD"): 160 patients without HNP and no radiculopathy, classic precondition for TDR; 2) group "HNP-No radiculopathy": 68 patients with HNP but without radiculopathy; 3) group "Stenosis": 73 patients without HNP but with radiculopathy, and 4) group "HNP-Radiculopathy": 132 patients with HNP and radiculopathy. The groups were compared regarding preoperative patient characteristics and pre- and postoperative VAS and EQ-5D scores using general linear modeling. RESULTS: Demographics in all four groups were comparable. Regarding the improvement of quality of life (EQ-5D) there were no differences across the four groups. For the two main groups DDD and HNP-Radiculopathy no differences were found in the adjusted postoperative back- and leg pain alleviation levels, in the stenosis group back- and leg pain relief were lower. CONCLUSIONS: Despite higher preoperative leg pain levels, outcomes in lumbar TDR patients with HNP and radiculopathy were similar to outcomes in patients with the classic indication; this because patients with higher preoperative leg pain levels benefit from a relatively greater leg pain alleviation. The group with absence of HNP but presence of radiculopathy showed considerably less benefits from the operation, which is probably related to ongoing degenerative processes of the posterior segmental structures. This observational multicenter study suggests that the diagnoses HNP and radiculopathy, combined or alone, may not have to be considered as absolute or relative contraindications for mono-segmental lumbar TDR anymore, whereas patients without HNP but with radiculopathy seem to be suboptimal candidates for the procedure.

Cervical disc arthroplasty compared with fusion in a workers' compensation population.

OBJECTIVE: Patients with cervical radiculopathy and/or myelopathy are often treated with anterior cervical discectomy and fusion. Cervical arthroplasty has recently been advocated as an alternative treatment. Theoretically, arthroplasty should permit early return to activity and protect against adjacent segment disease. Early mobilization and return to activity may, theoretically, reduce cost to the workers' compensation program. METHODS: A subgroup analysis of workers' compensation patients from the randomized controlled trials comparing Prestige ST and Bryan (Medtronic Sofamor Danek, Memphis, TN) cervical arthroplasty to fusion was performed. Primary outcome measures were work status, time to return to work, and neck disability. Secondary outcome measures were neck and arm pain and Medical Outcomes Study Short-Form 36-Item Health Survey score. RESULTS: One thousand four patients were enrolled in the studies, 93 of whom were workers' compensation patients. At 6 weeks and 3 months, significantly more patients in the arthroplasty group were working compared with the fusion group. At 6 months and later, there was no significant difference in return-to-work rates. Overall, patients returned to work at a median of 101 days after arthroplasty, compared with 222 days after anterior cervical discectomy and fusion. This difference was not significant when controlling for sex, study, and preoperative work status. At all time points, the Neck Disability Index was consistently lower in the arthroplasty group compared with the fusion group; however, the difference was not significant at 24 months. There was no statistically significant difference in secondary outcomes, neurological events, or pain-related events. CONCLUSION: In this workers' compensation cohort, it was observed that a greater number of patients in the arthroplasty group returned to work at 6 weeks and 3 months after surgery. A trend toward an earlier return to work was also seen, although this was not statistically significant when controlling for differences in the studies.

Avaliação da relação entre parâmetros antropométricos (peso e altura) e a topografia da raiz de L4 no espaço intertransversário L4-L5 através do acesso paramediano à coluna vertebral- Um estudo anatômico em vinte e um cadáveres / Assessment of the correlation between anthropometric parameters (weight and height) and the L4 root topography at the L4-L5 intertransverse space through paramedian access to the spine: an anatomic research on twenty one cadavers

As hérnias discais extremolaterais correspondem a 10 por cento das hérnias discais sintomáticas, mais comumente localizadas nos níveis L3-L4 e L4-L5. Por muitos anos, a abordagem cirúrgica das hérnias lombares foraminais e extraforaminais foi feita através de via de acesso posterior mediana com hemilaminectomia e facetectomia total ou parcial. A abordagem cirúrgica dessa patologia pela via paramediana, entre os músculos multífido e longuíssimo (via de Wiltse), tem a vantagem de poupar o paciente de perdas ósseas e permitir uma visão mais oblíqua do neuro-foramen. Essa abordagem permite, com mínima mobilização da raiz de L4, acesso ao disco L4-L5 e eventuais herniações extra-foraminais do mesmo. Nosso objetivo é avaliar se há relação entre características antropométricas de um indivíduo e a localização da raiz de L4 no espaço intertransversário, acessado pela via de Wiltse, para com isso poder antecipar alguns riscos cirúrgicos. Foram realizadas dissecções em 21 cadáveres (42 lados) e obtidas as respectivas medidas de peso e altura além da distância entre a base do processo transverso de L5 e o ponto onde a raiz de L4 o cruza. A análise dos dados nos permite concluir que não há relação estatisticamente significativa entre as variáveis envolvidas.

Far lateral disc hernias account for ten percent of all symptomatic disc hernias, usually located at L3-L4 and L4-L5 levels. For many years, the surgical approach to foraminal and extraforaminal lumbar disc hernias was provided through the median posterior access way, with total or partial hemilaminectomy and facetectomy. The advantage of the surgical approach for this pathology through the paramedian way, between the multifidus and longissimus muscles (Wiltse's access) is to spare patients from bone losses and to allow a more oblique view of the neuroforamen. Moreover, this approach allows for accessing the L4-L5 disc and its potential extraforaminal herniations with minimum L4 root mobilization. Our objective is to assess the potential correlation between anthropometric parameters and the L4 root topography. Twenty-one cadavers (42 sides) were dissected and some parameters were measured: cadavers' weight and height, width of the L5 transverse process, distance between L5 transverse process base and the point where the L4 root crosses it. The analysis of data allows us to conclude that no statistically significant correlation exists among the involved variables.

[Radiological diagnosis of lumbar prolaps with quantitative and morphological criteria]. / Die radiologische Befundung des lumbalen Bandscheibenvorfalls nach quantitativen und morphologischen Kriterien.

PURPOSE: The present study examines the differences of radiological diagnosis of lumbar prolaps with quantitative and morphological criteria. Advantages and disadvantages of both methods were analysed. METHOD: Concerning the "Deutsche Wirbelsäulenstudie" (DWS) 286 male and 278 female patients between 25 and 70 years of age undergoing clinical or ambulant therapy for radicular symptoms and the diagnosis of a lumbar prolaps in CT and/or MRT were integrated into our study. Actual MRT and CT pictures of the patients' lumbar spine were analysed by an independent radiologist (primary radiologist). Radiological diagnosis was concerned with quantitative and morphological criteria. Radiological images of 100 selected patients were reexamined by another radiologist (secondary radiologist). On the basis of these results, the interobserver reliability (kappa) was calculated. RESULTS: In 95.2% of all segments a prolaps was seen with quantitative and morphological criteria, in 4.5% a prolaps was analysed with quantitative and in 0.3% a prolaps was seen with morphological criteria. The radiological diagnosis of prolaps by quantitative criteria was confirmed by the operative findings. Many prolapses with lateral localisation were seen in these cases. Therefore radiological diagnosis on the basis of morphological criteria could be difficult. For both radiological methods similar interobserver reliabilities were calculated. To sum up both radiological methods are even equivalent. It is also possible to graduate the diagnosis with quantitative criteria. Detrimental effects of quantitative criteria could be difficulties in measurement with non-digital images. CONCLUSION: Besides several recommendations in the international literature on the radiological analysis of prolaps with morphological criteria, diagnosis with quantitative criteria is also an effective method.

Assessment of fusion after anterior cervical discectomy.

There is no established method to assess fusion in patients following anterior cervical discectomy. In this study we have made a series of measurements to detect movement between vertebrae adjacent to an operated space. The absence of movement implies structural union between adjacent vertebrae. Measurements have been made in two distinct surgical groups. Group A patients had anterior cervical discectomy with insertion of a BOP graft into the disc space. Group B patients underwent simple anterior cervical discectomy with no spacer or graft material inserted, the disc space being left empty. Details of the measurements and interpretation of results are described. In the absence of a 'gold standard' to assess bony union we propose that these measurement methods provide an objective and scientific method to assess fusion at the operated level after anterior cervical discectomy. Objective measurement of fusion will allow comparison between different surgical techniques that claim fusion as an end point. It will also become possible to study the influence of fusion on clinical outcome in different surgical populations.

Clinical assessment, MRI, and EMG in congenital brachial plexus palsy.

Thirteen infants with congenital brachial plexus palsy (eight with upper, five with upper and lower) were monitored by magnetic resonance imaging (the first performed between 7 and 41 days of age and the second at 3 months of age), electromyography (the first performed between 27 and 50 days and the second at 3 months), and the muscle scoring system of the Hospital for Sick Children (at 3, 6, and 9 months of age). The findings were evaluated with respect to the clinical status of the patients at 12 months of age. Magnetic resonance imaging, which could be performed readily even in the neonatal period, revealed pseudomeningoceles in two of the five patients with a poor prognosis (in all planes even in the early days after birth) and in two of the eight patients with a good prognosis (more easily visible at 3 months of age). Electromyography implied root avulsion in three of five patients with a poor prognosis. Electromyography can be of great value for patients with a poor prognosis and root avulsion but may underestimate the severity. The muscle scoring system (Hospital for Sick Children) was determined to be the most predictive method for prognosis.