Surgeon reported practice patterns related to full endoscopic cervical decompression procedures.

BACKGROUND: The microsurgical anterior approach to the cervical spine is commonplace. Fewer surgeons perform posterior cervical microsurgical procedures on a routine basis for lack of indication, more bleeding, persistent postoperative neck pain, and risk of progressive misalignment. In comparison, the endoscopic technique is preferentially performed through the posterior approach. Many spine surgeons and even surgeons versed in lumbar endoscopy are often reluctant to consider endoscopic procedures in the cervical spine. We report the results of a surgeon survey to find out why. METHODS: A questionnaire of 10 questions was sent to spine surgeons by email and chat groups in social media networks including Facebook, WeChat, WhatsApp, and LinkedIn to collect practice pattern data about microscopic and endoscopic spine surgery in the lumbar and cervical spine. The responses were cross-tabulated by surgeons' demographic data. Pearson Chi-Square measures, Kappa statistics, and linear regression analysis of agreement or disagreement were performed by analyzing the distribution of variances using the statistical package SPSS Version 27.0. RESULTS: The survey response rate was 39.7%, with 50 of the 126 surgeons who started the survey submitting a completed questionnaire. Of the 50 surgeons, 56.2% were orthopedic, and 42% neurological surgeons. Most surgeons worked in private practice (42%). Another 26% were university-employed, 18% were in private practice affiliated with a university, and the remaining 14% were hospital employed. The majority of surgeons (55.1%) were autodidacts. The largest responding surgeon groups were between 35-44 years (38%) and between 45-54 years of age (34%). Half of the responding surgeons were routinely performing endoscopic cervical spine surgery. The other half did not perform it for the main hurdle of fear of complications (50%). Lack of appropriate mentorship was listed as second most reason (25.4%). More concerns for not performing cervical endoscopic approaches were the perception of lack of technology (20.8%) and suitable surgical indication (12.5%). Only 4.2% considered cervical endoscopy too risky. Nearly a third (30.6%) of the spine surgeons treated over 80% of their cervical spine patients with endoscopic surgeries. Most commonly performed were posterior endoscopic cervical discectomy (PECD; 52%), posterior endoscopic cervical foraminotomy (PECF; 48%), anterior endoscopic cervical discectomy (AECD; 32%), cervical endoscopic unilateral laminotomy for bilateral decompression (CE-ULBD; 30%), respectively. CONCLUSION: Cervical endoscopic spine surgery is gaining traction among spine surgeons. However, by far most surgeons performing cervical endoscopic spine surgery work in private practice and are autodidacts. This lack of a teacher to shorten the learning curve as well as fear of complications are two of the major impediments to the successful implementation of cervical endoscopic procedures.

A biomechanical comparison of a cement-augmented odontoid screw with a posterior-instrumented fusion in geriatric patients with an odontoid fracture type IIb.

PURPOSE: Possible surgical therapies for odontoid fracture type IIb include odontoid screw osteosynthesis (OG) with preservation of mobility or dorsal C1/2 fusion with restriction of cervical rotation. In order to reduce material loosening in odontoid screw osteosynthesis in patients with low bone density, augmentation at the base of the axis using bone cement has been established as a suitable alternative. In this study, we compared cement-augmented OG and C1/2 fusion according to Harms (HG). METHODS: Body donor preparations of the 1st and 2nd cervical vertebrae were randomized in 2 groups (OG vs. HG). The range of motion (ROM) was determined in 3 principle motion plains. Subsequently, a cyclic loading test was performed. The decrease in height of the specimen and the double amplitude height were determined as absolute values as an indication of screw loosening. Afterward, the ROM was determined again and loosening of the screws was measured in a computed tomography. RESULTS: A total of 16 were included. Two groups of 8 specimens (OG vs. HG) from patients with a median age of 80 (interquartile range (IQ) 73.5-85) years and a reduced bone density of 87.2 (IQ 71.2-104.5) mg/cc dipotassium hydrogen phosphate were examined for their biomechanical properties. Before and after exposure, the OG preparations were significantly more mobile. At the time of loading, the OG had similar loading properties to HG decrease in height of the specimen and the double amplitude height. Computed tomography revealed similar outcomes with regard to the screw loosening rate (62.5 vs. 87.5%, p = 0.586). CONCLUSION: In patients with an odontoid fracture type IIb and reduced bone density, cement-augmented odontoid screw yielded similar properties in the loading tests compared to the HG. It may, therefore, be considered as a primary alternative to preserve cervical mobility in these patients.

Assessment of Skin Flaps Above Cranial Defects Following Craniectomy: A Proposed Classification System.

OBJECTIVE: The assessment of the skin flap above cranial defects (SCD) following craniectomy is routine in neurosurgical practice, and a change in the consistency of the skin flap may indicate raised intracranial pressure or the occurrence of a complication necessitating intervention. The purpose of this study was to develop a clinically useful classification system based on clinical assessment of the degree of skin flap bulging or sinking and its firmness. PATIENTS AND METHODS: This was a prospective single-center study. The SCDs of consecutive patients who underwent craniectomy were assessed daily by two trained independent examiners. The consistency of the flap and its bulging or sinking in comparison with the level of the cranium were noted. Testing conditions including the positioning of the patient and examiner were standardized. RESULTS: A total of 520 examinations were conducted in 24 patients during their hospital stay. There was 100% interrater reliability (Cohen's κ = 1.0). In 66.6% of all patients (n = 16/24), a change of the SCD classification in comparison with that recorded on the previous day was noted. CONCLUSIONS: The SCD classification facilitates the reproducible and objective assessment of SCDs, enabling reliable monitoring over time and between individuals.

Penetrating traumatic brain injury resulting from a cockerel attack: case report and literature review.

Traumatic brain injury is common in children and can lead to death or considerable, long-lasting morbidity. We present the case of a 10-month-old female child who presented after being attacked by a cockerel in a chicken coop. Following a seizure, an MRI scan revealed an intracerebral haemorrhage underlying a stab-type wound inflicted by the bird. Animal bite injuries are common worldwide but they rarely cause intracranial injuries. Domestic hens are rarely dangerous but can become defensive or aggressive during breeding periods or when protecting their territory. To date, only a handful of articles have reported on wounds inflicted by chicken beaks. Those reported were largely facial or ocular injuries. Infectious complications have also been encountered post-injury. This is to our knowledge the first report of a bird attack resulting in significant penetrating traumatic brain injury. Children should be cautioned by guardians to avoid unsupervised contact with chickens, particularly during breeding. Attacks to the neurocranium when they occur must be taken seriously and not treated as humorous or insignificant. Imaging appropriate to the child's clinical condition should be pursued and appropriate intervention and antibiotic treatment should be implemented.

Prospective randomized comparison of early versus newer-generation vertebral access devices for kyphoplasty.

INTRODUCTION: Kyphoplasty is an established method of treating osteoporotic vertebral body compression fractures. In recent years, several techniques to enhance the efficiency and outcomes of this surgery have been developed and implemented in clinical practice. In the present study, we assess the impact of two new access instruments on overall operation time and the administered dose area product in comparison with the standard access instrument used in our clinical practice. The two newer comparator devices have been designed with the intention of streamlining intraoperative workflow by omitting several procedural steps. MATERIALS AND METHODS: This was a single-center prospective randomized trial investigating three distinct access instruments compatible with the Joline Allevo balloon catheter system. Specifically, two newer access devices marketed as being able to enhance surgical workflow (Joline RapidIntro Vertebra Access Device with a trocar tip and Joline SpeedTrack Vertebra Introducer Device with a short, tapered tip) were compared with the older, established Joline Vertebra Access Device from the same firm. Consecutive eligible and consenting patients scheduled to undergo kyphoplasty for osteoporotic vertebral compression fracture refractory to conservative, medical treatment during the period May 2012-August 2015 were randomized to receive surgery using one of the three devices. Besides the use of the trial instruments, all other preoperative, intraoperative and postoperative care was delivered according to standard practice. RESULTS: 91 kyphoplasties were performed on 65 unique patients during the study period. The median operation time across the three groups was 29 min (IQR 22.5-35.5) with a median irradiation time of 2.3 min (IQR 1.2-3.4). The median patient age was 74 years (IQR 66-80). The groups did not significantly differ in terms of age (p = 0.878), sex (p = 0.37), T score (p = 0.718), BMI (p = 0.285) or the applied volume of cement (p = 0.792). There was no significant difference between the treatment groups with respect to surgical duration (p = 0.157) or dose area product (p = 0.913). CONCLUSIONS: Although use of the two newer-generation access instruments were designed to involve fewer unique steps per operation, their use was not associated with reduction in surgical duration, irradiation time or dose area product administered compared with the older, established vertebral access device. Care should be taken to evaluate the impact of new instruments on key surgery-related parameters such as surgical duration and radiation exposure and claims made about new instruments should be assessed a structured fashion.

High-Resolution PET Cisternography With 64Cu-DOTA for CSF Leak Detection.

Intracranial hypotension may lead to chronic, debilitating symptoms, and severe complications. The underlying CSF leak may be difficult to localize. To establish a new diagnostic option for the detection of CSF leaks, Cu-DOTA was developed as a tracer for PET imaging. PET/CT imaging was possible with high resolution and without complications. In one patient, the exact site of a dural tear was identified, enabling successful surgical treatment. PET cisternography with Cu-DOTA appears to be safe and able to locate a CSF leak. It has the potential to be a problem-solving modality in cases with inconclusive CT, MR, and/or scintigraphic findings.

Cement-augmented anterior odontoid screw fixation in elderly patients with odontoid fracture.

OBJECTIVES: Osteoporotic bone predisposes to hardware loosening in patients with odontoid fracture treated with anterior odontoid screw fixation. Cement augmentation is an established method to increase screw anchorage in such cases. The aim of this study was to determine the intra- and perioperative surgical complications of this technique and a comparison with a non-cement augmented group. PATIENTS AND METHODS: During the period January 2012 to November 2017, 24 elderly patients with odontoid fractures and reduced bone mineral density were treated with cement-augmented anterior odontoid screw fixation. Demographic and clinico-anatomical parameters were contemporaneously recorded. A comparison group of 28 elderly patients treated with odontoid screw fixation without cement-augmentation was used to determine the difference of bone fusion rate and whether cement-augmentation extended surgery duration. RESULTS: 24 patients (18 female, 6 male) were treated with cement-augmented anterior odontoid screw fixation during the study period. The median patient age was 84 years (IQR 81-86 years). In 6/24 cases, asymptomatic cement leakage occurred. Five of these cases involved prevertebral cement leakage into the longus colli muscle. In the other case, cement leaked into the C2/3 joint. There was no significant difference in the time required to perform cement-augmented anterior screw fixation compared to fixation without cement-augmentation (median 65 min versus 56.5 min; p = .119). After a median follow-up of 11 months, the bony-fusion rate in the cement-augmented group was 75% (15/24 patients) versus 50% in the non-cement-augmented group (11/28 patients; p = .096). Revision surgery was necessary in none of the cases in the cement-augmented group and in three cases in the non-cement-augmented group (10.7%; p=.048). CONCLUSION: Additional cement augmentation for anterior odontoid fracture repair is a feasible and safe procedure in elderly patients with reduced bone mineral density. Moreover, given that cement-augmentation was associated with a trend towards a higher rate of medium-term bony fusion and a lower revision surgery rate, it is a treatment strategy that should be considered in the management of elderly patients with type IIb odontoid fractures.

Risk Factors for Adjacent Fractures After Cement-Augmented Thoracolumbar Pedicle Screw Instrumentation.

BACKGROUND: The aim of our study was to identify factors that influence the occurrence of adjacent fractures in patients with cement-augmented pedicle screw instrumentation. METHODS: Data were retrospectively collected from medical charts and operative reports for every surgery in which cement-augmented instrumentation was used in our hospital of 4 consecutive years. A total of 93 operations were included and examined for gender, age, T-score, number of fused segments, number of implanted screws, broken screws, loosening of screws, leakage and distribution pattern of cement, pre- and postoperative kyphosis angle, revision surgery and adjacent fractures in follow-up. Categorical data were compared using the χ2 test or by Fisher's exact test, as appropriate. Continuous variables conforming to a normal distribution were compared using Student's t test. Otherwise the Mann-Whitney U test was applied. A P-value of <.05 was considered statistically significant. A trend was defined as a P < .2. RESULTS: The mean age was 68.1 years with a mean T-score of -3.12. Nineteen adjacent fractures occurred during follow-up and the median follow-up was 12 months (range, 1-27). Patients showed a higher risk for adjacent fractures following revision surgery (P = .016). Most fractures occurred superior to the instrumented level (P = .013) and in the first 12 months. Difference of T-score between the group "no adjacent fracture" and the group "adjacent fracture" was 0.7 (P = .138). Another trends were found in greater age (P = .119) and long instrumentations (P = .199). CONCLUSIONS AND CLINICAL RELEVANCE: Revision surgeries are associated with a higher risk of adjacent fractures. In these cases, prophylactic kyphoplasty of the superior vertebra should be considered. This study is a retrospective, nonrandomized cohort/follow-up study. LEVEL OF EVIDENCE: 3.

Not your average Saturday night palsy-High resolution nerve ultrasound resolves rare cause of wrist drop.

We present a case of a patient with acute wrist drop caused by radial nerve torsion. NCS showed axonal lesion of the radial nerve. High-resolution ultrasound was able to visualize a constriction of the radial nerve. Nerve torsion is a rare differential diagnosis to Saturday night palsy. The patient was subjected to early surgical intervention and showed a favorable outcome in follow-up. Thus, high-resolution ultrasound may subject these patients early to surgical therapy.

Complete evaluation of pituitary tumours in a single tertiary care institution.

INTRODUCTION: We retrospectively evaluated all patients with pituitary tumours treated in our department from 1/1/1997 to 01/11/2014. PATIENTS AND METHODS: Two hundred and fifteen patients (124 females, 91 males, mean age 50.9 years) were treated because of pituitary tumours. All patients underwent basal hormonal analysis and when required dynamic testing in order to check for hormonal activity. Pituitary masses were divided into groups concerning their hormonal status and were further classified according to gender, age at diagnosis, tumour size, and the development of postoperative pituitary insufficiency when neurosurgical intervention was conducted. RESULTS: One hundred and twenty-one patients had hormonally inactive tumours (non-functional adenomas; 56.3%), 57 prolactinomas (26.5%), 17 growth hormone secreting adenomas (7.9%), 16 Cushing's disease (7.4%), and 4 craniopharyngiomas (1.9%). Tumours with maximum size <1 cm (microadenomas) were detected in 62 patients (28.8%) and ≥1 cm (macroadenomas) in 153 (71.2%) of all cases (rate 1:2.5). Ninty eight patients (45.6%) had surgery (87 transsphenoidal and 11 transcranial), of this group 34 with hormonally active tumours (37.8% of the 90 patients of this subcohort). Indications for surgery were an increased risk or manifestation of chiasma syndrome and clinical symptoms due to hormonal hypersecretion. Complete [32 cases (32.6%)] or partial [33 cases (33.7%)] postoperative insufficiency in minimum one pituitary axis was present in 65/98 (66.3%) of the operated patients. CONCLUSIONS: Pituitary adenoma prevalence is rising due to widely available imaging procedures. The majority of the tumours in our cohort were macroadenomas and hormonally inactive. Tumour extirpation via the transsphenoidal or transcranial route resulted in functional pituitary impairment of variable extent in 2/3 of the patients.

Time course of the response to navigated repetitive transcranial magnetic stimulation at 10 Hz in chronic neuropathic pain.

Objective This prospective study evaluated the time to response and outcomes of navigated repetitive transcranial magnetic stimulation (TMS) at a frequency of 10 Hz in patients with chronic neuropathic pain. Methods This prospective study included patients with unilateral chronic neuropathic pain. All patients received motor cortex stimulation at 10 Hz over nine consecutive days using repetitive TMS. Outcome was evaluated over a six-week follow-up period using the visual analogue scale, the German Pain Questionnaire and time to pain reduction. Results Fifty patients (23 female, 27 male) were recruited. Two patients were excluded from analysis owing to premature discontinuation of treatment and follow-up. 31/48 patients in the cohort suffered from atypical facial pain. The pain duration ranged approximately from six months to 27 years. After six weeks, 28/46 patients reported a significant level of pain relief (P < 0.001). Conclusion Navigated repetitive TMS for chronic pain is a non-invasive modality with demonstrable clinical benefit. In particular, patients with atypical facial pain with a clear clinicoanatomical correlate responded well to high-frequency stimulation. Patients with a mean pain history of less than five years benefited significantly from this treatment, so early treatment with repetitive TMS should be encouraged.

Cost-effectiveness of the long-term use of temozolomide for treating newly diagnosed glioblastoma in Germany.

Concomitant radiochemotherapy followed by six cycles of temozolomide (= short term) is considered as standard therapy for adults with newly diagnosed glioblastoma. In contrast, open-end administration of temozolomide until progression (= long-term) is proposed by some authors as a viable alternative. We aimed to determine the cost-effectiveness of long-term temozolomide therapy for patients newly diagnosed with glioblastoma compared to standard therapy. A Markov model was constructed to compare medical costs and clinical outcomes for both therapy types over a time horizon of 60 months. Transition probabilities for standard therapy were calculated from randomized controlled trial data by Stupp et al. The data for long-term temozolomide therapy was collected by matching a cohort treated in the Department of Neurosurgery at Jena University Hospital. Health utilities were obtained from a previous cost utility study. The cost perspective was based on health insurance. The base case analysis showed a median overall survival of 17.1 months and a median progression-free survival of 7.4 months for patients in the long-term temozolomide therapy arm. The cost-effectiveness analysis using all base case parameters in a time-dependent Markov model resulted in an incremental effectiveness of 0.022 quality-adjusted life-years (QALYs). The incremental cost-effectiveness ratio (ICER) was €351,909/QALY. Sensitivity analyses showed that parameters with the most influence on ICER were the health state utility of progression in both therapy arms. Although open-ended temozolomide therapy is very expensive, the ICER of this therapy is comparable to that of the standard temozolomide therapy for patients newly diagnosed with glioblastoma.

Prediction of 30-day mortality in spontaneous cerebellar hemorrhage.

BACKGROUND: Cerebellar hemorrhage is a potentially life-threatening condition and an understanding of the factors influencing outcome is essential for sound clinical decision-making. METHODS: We retrospectively evaluated data from 50 consecutive patients who suffered a first spontaneous cerebellar hemorrhage (SCH) from 2005 to 2014, analysing their short-term outcomes and identifying possible clinical, radiological and therapeutic risk factors for poor prognosis and death within 30 days. RESULTS: Among 50 patients with first SCH, the mean age was 72 ± 10 years. Median Glasgow Coma Scale (GCS) score on admission was 11 [interquartile range (IQR) = 7-11]. Among 50 patients, 19 patients (38%) underwent surgical hemorrhage evacuation with placement of an external ventricular drain (EVD), 12 patients (24%) received an EVD only and 19 patients (38%) were treated conservatively. The 30-day mortality rate was 36%. In multivariate analysis only the GCS score on admission was a significant predictor of 30-day mortality [odds ratio (OR) = 0.598; 95% confidence interval (CI) = 0.406-0.879; P = 0.009]. For prediction of 30-day mortality, receiver operating characteristic curve analysis confirmed that the best cut-off point was a GCS score of 10 on admission [area under the curve: 0.882, 95% CI = 0.717-1, P < 0.001]. CONCLUSION: Lower GCS score on admission was associated with increased 30-day mortality and poorer short-term outcome in patients with SCH. For patients with a GCS score <10 on admission, it is important to balance the possibility of survival afforded by further therapy against the formidable risk of significant functional disability and poor quality of life.

Cement-augmented anterior odontoid screw fixation for osteoporotic type II odontoid fractures in elderly patients: prospective evaluation of 11 patients.

PURPOSE: Osteoporosis is considered to be a relative contraindication for anterior screw fixation of odontoid fractures because of reduced screw purchase. In the presence of osteoporosis, the most frequent mode of implant failure is via cut-out through the anterior wall of C2. Under in vitro conditions, cement-augmented odontoid screws show significant biomechanical advantages as compared to non-augmented screws. Against this background, we present our prospectively collected data on cement-augmented anterior screw fixation of osteoporotic odontoid fractures in elderly patients. METHODS: 11 patients (8 female, 3 male, median age 83 years, range 73-89 years) with an isolated, osteoporotic type II odontoid fracture were treated. After closed reduction and standard anterior approach to the C2/3 level, a self-tapping, short-threaded 3.5-mm lag screw was placed. High-viscosity polymethylmethacrylate cement was injected via a cannulated Jamshidi needle into the base of the C2 vertebral body around the screw shaft and the screw was further tightened. Thin slice CT reconstructions for follow-up evaluation were done consistently postop and 12 months after surgery. RESULTS: Anatomic fracture reposition was achieved in all patients. Cement application was uneventful and well controllable. Cement leakage towards the fracture gap was not detectable. There were no major perioperative complications and no early revision surgeries. After 1 year, thin slice CT with three-dimensional reconstruction demonstrated solid osseous healing of the odontoid fracture in 8 out of 10 patients. CONCLUSIONS: Additional cement augmentation for anterior odontoid fracture repair is technically easy and safe. In elderly people with osteoporotic odontoid fractures, the procedure seems to be a useful supplementary option.

Spontaneous Involution of a Presumably Rathke's Cleft Cyst in a Patient with Slight Subclinical Hypopituitarism: A Case Report and Review of the Literature.

Rathke cleft cyst is described as benign intrasellar cyst. They are mostly small and asymptomatic; they may become large enough to cause symptoms by compression of intrasellar or suprasellar structures. We report on a case of spontaneous regression of a symptomatic RCC with subsequent recovery of preexisting endocrine dysfunction and resolution of headaches. A 60-year-old man complained about headaches. Laboratory investigation revealed a partial hypopituitarism with a slight central hypothyroidism without need for substitution. An MRI study showed a cystic, T2-hyperintense, sellar lesion compatible with a RCC. At one year follow-up, the patient had no complaints and the hormone work-up revealed a regression of the previous slight hypopituitarism. The MRI study showed a complete regression of the cystic lesion and a normal sized and shaped pituitary gland. The spontaneous regression of cystic sellar lesions is rare. The exact mechanism of the possible spontaneous involution of RCC is until now not well understood. However, spontaneous regression is possible and justifies the conservative therapy with regular clinical and radiological follow-up for asymptomatic patients or patients with symptoms not caused by the mass effect of these lesions.

Cement augmented anterior odontoid screw fixation is biomechanically advantageous in osteoporotic patients with Anderson Type II fractures.

STUDY DESIGN: A biomechanical human cadaveric study. OBJECTIVE: The authors tested a cannulated and perforated lag screw and compared in situ polymethylmethacrylate (PMMA) augmentation against nonaugmentation for fixation of osteoporotic type II odontoid fractures. SUMMARY OF BACKGROUND DATA: Osteoporosis has been identified as a strong predictor for pseudarthrosis after screw fixation of type II odontoid fractures with cut-out through the anterior wall of C2 as the most frequent mode of implant failure. The concept of PMMA augmentation of the proximal screw shank could serve as a useful supplement in this context. METHODS: A total of 18 fresh-frozen human cadaveric C2 vertebrae were harvested (median 86.5 y; range, 69-98 y). Reduced bone quality was verified by quantitative computed tomography. Type II odontoid fractures were created and repaired with a cannulated lag screw, which has perforations in the proximal screw shank. Additional PMMA augmentation was carried out for 9 specimens. The position of the screw and cement distribution were evaluated by computed tomography. Values for maximum force to failure, energy to failure, and stiffness were statistically compared between cement augmented and nonaugmented screws. RESULTS: Cement distribution in the C2 vertebral body was circumferential around the screw shank without leakage into the spinal canal or into the fracture gap in all 9 specimens. The cement augmented screws showed a 2.4 times higher maximum force to failure (363±94 N, P<0.001), a 2.7 times higher energy to failure (1300±698 mJ, P<0.001), and a 1.76 times higher stiffness (90±35 N/mm, P=0.031) in comparison with the nonaugmented screws. CONCLUSIONS: Cement augmentation for fixation of osteoporotic type II odontoid fractures showed biomechanical advantages. It was also shown that cement augmentation of the newly developed screw is technically easy and safe under in vitro conditions. The technique might be useful with regard to the surgical treatment of elderly patients with osteoporotic odontoid fractures.

Denervation and atrophy of paraspinal muscles after open lumbar interbody fusion is associated with clinical outcome--electromyographic and CT-volumetric investigation of 30 patients.

BACKGROUND: Different studies have shown that atrophy of paraspinal muscles arises after open dorsal lumbar fusion, and the reasons for this atrophy are still not yet fully clarified. This prospective study investigates the extent of atrophy of the lumbar paraspinal muscles after open lumbar interbody fusion, its possible causes, and their association with clinical outcome measures. METHODS: Thirty consecutive patients were prospectively included (13 male, 17 female, median age 60.5 years, range 33-80 years). Mono or bisegmental, posterior lumbar interbody fusion and instrumentation was performed applying a conventional, open lumbar midline approach. Clinical outcome was assessed by the Short Form (36) Health Survey (SF-36) questionnaire and visual analogue scale. Needle electromyography of paraspinal muscles was performed preoperatively, at 6 and 12 months. Serum values of creatine kinase, lactate dehydrogenase and myoglobin were determined preoperatively, at day 2 after surgery and at discharge. Paraspinal muscle volume was determined by volumetric analysis of thin-slice computed tomography scans preoperatively and 1 year after surgery. RESULTS: There was a significant increase of electromyographic denervation activity (p =0.024) and reduced recruitment of motor units (p = 0.001) after 1 year. Laboratory studies showed a significant increase of CK (p < 0.001) and myoglobin (p < 0.001) serum levels at day 2 after surgery. The paraspinal muscle volume decreased from 67.8 to 60.4 % (p < 0.001) after 1 year. Correlation analyses revealed a significant negative correlation between denervation and muscle volume (K = -0.219, p = 0.002). Paraspinal muscle volume is significantly correlated with physical outcome (K = 0.169, p = 0.020), mental outcome (K = 0.214, p = 0.003), and pain (K = 0.382, p < 0.001) after 1 year. CONCLUSIONS: Atrophy of paraspinal muscles after open, posterior lumbar interbody fusion seems to be associated with denervation, as well as direct muscle trauma during surgery. While muscle atrophy is also correlated with a worse clinical outcome, it seems to be a determining factor for successful lumbar spine surgery.

Degenerative lumbar spinal stenosis in older people: current treatment options.

BACKGROUND: Degenerative lumbar spinal stenosis is increasingly being diagnosed in persons over age 65. In 2011, 55 793 older people with this condition were treated as inpatients in German hospitals. Among physicians, there is much uncertainty about the appropriate treatment strategy. METHOD: Selective literature review. RESULTS: Lumbar spinal stenosis in older people is characterized by spinal claudication and neurological deficits. A precise clinical history and physical examination and ancillary radiological studies are the necessary prerequisites for treatment. Magnetic resonance imaging is the radiological study of choice. Conservative treatment consists of physiotherapy, drugs, and local injections; various surgical treatments can be considered, depending on the severity of the problem. The main purpose of surgery is to decompress the spinal canal. If the lumbar spine is demonstrably unstable, an instrumented fusion should be performed in addition. There is, however, only moderately good evidence supporting the superiority of surgery over conservative treatment. In a prospective study, the complication rate of purely decompressive surgery was found to be 18%. The utility of the current operative techniques cannot be definitively assessed, because they are applied to a wide variety of patients in different stages of the disease and at different degrees of severity, and the reported results are thus not comparable from one trial to another. CONCLUSION: No evidence-based recommendation on the diagnosis and treatment of lumbar spinal stenosis in older people can be formulated at present because of the lack of pertinent randomized trials.

Risk factors of aseptic bone resorption: a study after autologous bone flap reinsertion due to decompressive craniotomy.

OBJECT: In patients who have undergone decompressive craniectomy, autologous bone flap reinsertion becomes necessary whenever the cerebral situation has consolidated. However, aseptic necrosis of the bone flap remains a concern. The aim of this study was to report possible perioperative complications in patients undergoing autologous bone flap reinsertion and to identify the risk factors that may predispose the bone flap to necrosis. METHODS: All patients admitted to the authors' neurosurgical department between September 1994 and June 2011 and who received their own cryoconserved bone flap after decompressive craniectomy were studied. The grade of the bone flap necrosis was classified into 2 types. Type II bone necrosis was characterized by aseptic resorption with circumscribed or complete lysis of tabula interna and externa requiring surgical revision. To define predisposing factors, a multivariate analysis was performed using bone necrosis as the dependent variable. RESULTS: Among the 372 patients (mean age 48.6 years, 57.4% males) who received 414 bone flaps during the observation period, 134 (36.0%) had a diffuse traumatic brain injury, 69 (18.5%) had subarachnoid hemorrhage, 58 (15.6%) had cerebral infarction, 56 (15.1%) had extraaxial bleeding, 43 (11.6%) had intracerebral bleeding, and 12 (3.2%) had a neoplasm. Surgical relevant Type II bone flap necrosis occurred in 85 patients (22.8%) and 91 bone flaps, after a median time of 15 months (interquartile range [IQR], 10-33 months). In a multivariate analysis with Type II necrosis as the dependent variable, bone flap fragmentation with 2 (OR 3.35, 95% CI 1.59-7.01, p < 0.002) or more fragments (OR 24.00, 95% CI 10.13-56.84, p < 0.001), shunt-dependent hydrocephalus (OR 1.76, 95% CI 0.99-3.12, p = 0.04), and a younger age (OR 0.98, 95% CI 0.96-0.99, p = 0.004) was associated with a higher risk for the development of an aseptic bone flap necrosis. CONCLUSIONS: In patients undergoing bone flap reinsertion after craniotomy, aseptic bone necrosis is an underestimated problem during long-term follow-up. Especially in younger patients with an expected good neurological recovery and a fragmented bone flap, an initial allograft should be considered because of an increased risk for aseptic bone flap necrosis.