Do TLIF and PLIF Techniques Differ in Perioperative Complications? - Comparison of Complications Rates of Two High Volume Centers.

STUDY DESIGN: Retrospective bicentric Cohort Study. OBJECTIVE: Posterior (PLIF) and transforaminal lumbar interbody fusion (TLIF) have been clinically proven for the surgical treatment of degenerative spinal disorders. Despite many retrospective studies, the superiority of either technique has not been proven to date. In the literature, the complication rate of the conventional PLIF technique is reported to be significantly higher, but with inconsistent complication recording. In this retrospective bicentric study, a less invasive PLIF technique was compared with the conventional TLIF technique and complications were recorded using the validated SAVES V2 classification system. METHODS: 1142 patients underwent PLIF (702) or TLIF (n = 440) up to 3 levels in two specialized centers. Epidemiological data, intra- and postoperative complications during hospitalization and after discharge were analyzed according to SAVES V2. RESULTS: The overall complication rate was 13.74%. TLIF-patients had slightly significant more complications than PLIF-patients (TLIF = 16.6%/PLIF = 11.9%, P = .0338). Accordingly, complications during revision surgeries were more frequent in the first cohort (TLIF = 20.9%/PLIF = 12.6%; P = .03252). In primary interventions, the surgical technique did not correlate with the complication rate (TLIF = 12.4%/PLIF = 11.7%). There were no significant differences regarding severity of complications. CONCLUSIONS: An important component of this work is the complication recording according to a uniform classification system (SAVES V2). In contrast to previous literature, we could demonstrate that there is not a significant difference between the two surgical techniques.

AO Spine Guideline for the Use of Osteobiologics (AOGO) in Anterior Cervical Discectomy and Fusion for Spinal Degenerative Cases.

STUDY DESIGN: Guideline. OBJECTIVES: To develop an international guideline (AOGO) about the use of osteobiologics in anterior cervical discectomy and fusion (ACDF) for treating degenerative spine conditions. METHODS: The guideline development process was guided by AO Spine Knowledge Forum Degenerative (KF Degen) and followed the Guideline International Network McMaster Guideline Development Checklist. The process involved 73 participants with expertise in degenerative spine diseases and surgery from 22 countries. Fifteen systematic reviews were conducted addressing respective key topics and evidence was collected. The methodologist compiled the evidence into GRADE Evidence-to-Decision frameworks. Guideline panel members judged the outcomes and other criteria and made the final recommendations through consensus. RESULTS: Five conditional recommendations were created. A conditional recommendation is about the use of allograft, autograft or a cage with an osteobiologic in primary ACDF surgery. Other conditional recommendations are about the use of osteobiologic for single- or multi-level ACDF, and for hybrid construct surgery. It is suggested that surgeons use other osteobiologics rather than human bone morphogenetic protein-2 (BMP-2) in common clinical situations. Surgeons are recommended to choose 1 graft over another or 1 osteobiologic over another primarily based on clinical situation, and the costs and availability of the materials. CONCLUSION: This AOGO guideline is the first to provide recommendations for the use of osteobiologics in ACDF. Despite the comprehensive searches for evidence, there were few studies completed with small sample sizes and primarily as case series with inherent risks of bias. Therefore, high-quality clinical evidence is demanded to improve the guideline.

Cervical Single-Level Pincer Stenosis Causing Myelopathy: A Technical Note and Medium-term Results of a One-Session Microsurgical 360-Degree Treatment.

BACKGROUND AND STUDY AIMS: Single-level circumferential or pincer stenosis (PS) affects few patients with degenerative cervical myelopathy (DCM). The surgical technique and medium-term results of a one-session microsurgical 360-degree (m360°) procedure are presented. PATIENTS: Between 2013 and 2018, the data of 23 patients were prospectively collected out of 371 patients with DCM. The m360° procedure comprised a microsurgical anterior cervical decompression and fusion (ACDF), with additional plate fixation, followed by flipping the patient and performing a microsurgical posterior bilateral decompression via a unilateral approach in crossover technique. RESULTS: The mean age of the patients was 72 years (range: 50-84); 17 patients were males. The mean follow-up time was 12 months (range: 6-31). The patients filled in the patient-derived modified Japanese Orthopaedic Association (P-mJOA) questionnaire on average 53 months after surgery. One patient received a two-level ACDF. Lesions were mostly (92%) located at the C3/C4 (8/24), C4/C5 (7/24), and C5/C6 (7/24) levels. Functional X-rays showed segmental instability in 10 of 23 patients (44%). All preoperative T2-weighted magnetic resonance imaging (MRI) showed an intramedullary hyperintensity. The median preoperative mJOA score was 13 (range 3), and it improved to 16 (range 3) postoperatively. The mean improvement rate in the mJOA score was 73%. When available, postoperative MRI confirmed good circumferential decompression with persistent intramedullary hyperintensity. There were two complications: a long-lasting radicular paresthesia at C6 and a transient C5 palsy. No revision surgery was required. CONCLUSION: The one-session m360° procedure was found to be a safe surgical procedure for the treatment of PS, and the medium-term clinical outcome was satisfactory.

Surgical Treatment of Multilevel Degenerative Cervical Myelopathy: Open-Door Laminoplasty and Fixation via Unilateral Approach. A Feasibility Study.

OBJECTIVE: We compared open-door laminoplasty via a unilateral approach and additional unilateral lateral mass screw fixation (uLP) with laminectomy and bilateral lateral mass screw fixation (LC) in the surgical treatment of multilevel degenerative cervical myelopathy (mDCM). METHODS: A retrospective cohort analysis of 46 prospectively enrolled patients (23 uLP and 23 LC). The minimum follow-up was 1 year. Neck and arm pains were evaluated with visual analog scales and disability with the Neck Disability Index (NDI). Myelopathy was rated with the modified Japanese Orthopaedic Association (mJOA) score. Cervical sagittal parameters were measured on plain and functional X-ray films with a specific software. The statistical significance was set at p < 0.05. Fusion was defined as <2 degrees of intersegmental motion on flexion/extension radiographs. RESULTS: The two groups were similar in age and comorbidities. The mean operation time and the mean hospital stay were shorter in the uLP group (p = 0.015). The intraoperative blood loss did not exceed 200 mL in both groups. At follow-up, the groups showed comparable clinical outcome data. The sagittal profile did not deteriorate in either group. Fusion rates were 67% in the uLP group and 92% in the LC group. No infections occurred in either group. In the LC group, one patient developed a transient C5 palsy. Revision surgery was required for a malpositioned screw (LC) and for one implant failure (uLP). CONCLUSION: Laminoplasty and unilateral fixation via a unilateral approach achieved comparable clinical and radiologic results with laminectomy and bilateral fixation, despite a lower fusion rate. However, the surgical traumatization was less.

Revision surgery in cervical spine.

PURPOSE: To report the indications, presurgical planning, operative techniques, complications for making decisions in cervical revision surgery (CRS). METHODS: Hundred and two patients underwent CRS over a four-year period. Epidemiological data, the type of first surgery, CRS surgical techniques and complications were retrospectively evaluated. Pain and neurological symptoms were assessed according to the validated Odom criteria. CRS indications were classified into five categories: adjacent segment disease (ASD), infection (INF), implant failure-pseudarthrosis (IFP), non-infectious complication, and deformity. Patients were classified into three groups, according to the approach of the index procedure: anterior, posterior, or 360°. RESULTS: The mean patient age was 63 years (59% males). ASD (40%), INF (23%), and IFP (22%) were observed in 85% of patients. CRS was performed with the same approach that was used in the index procedure in 64% of the anterior group and in 83% of the posterior group. In the 360° group, 64% of CRSs was performed with a posterior access. The early complication rate was 4.9%. The outcome was excellent in 19 patients (19%), good in 37 patients (36%), satisfactory in 27 patients (26%), and poor in six patients (6%). Thirteen patients (13%) were lost to follow-up. No implants failed radiologically or required surgical revision. CONCLUSIONS: CRS required painstaking planning and mastery of a variety of surgical techniques. The results were rewarding in half and satisfactory in a quarter of the patients. The complication rate was lower than expected. In the most complex cases, referral to a specialized center is recommended. These slides can be retrieved under Electronic Supplementary Material.

The clinical significance of redundant nerve roots of the cauda equina in lumbar spinal stenosis patients: A systematic literature review and meta-analysis.

OBJECTIVES: Decompression surgery for lumbar spinal stenosis (LSS) is the most performed spine surgery procedure in patients older than 65 years. Around 40% of LSS patients scheduled for decompression surgery have evidence of redundant nerve roots (RNR) of the cauda equina on their magnetic resonance images (MRI). Little is known about the clinical significance of RNR in LSS patients. The objective was to assess the effects of RNR on clinical scores and recovery in older adults diagnosed with LSS. PATIENTS AND METHODS: A systematic literature search was performed in April 2018 on PubMed, Web of Science, MEDLINE and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Prospective and retrospective cohort studies undertaken to assess differences in clinical outcomes in patients diagnosed with LSS with versus without evidence of RNR on their MRIs were selected. Two authors independently selected studies, abstracted data and assessed risk of bias. We calculated weighted mean differences (WMD) for continuous variables and odds ratio (OR) for variables reported in frequencies. RESULTS: Seven studies comprising a total of 1046 LSS patients were included in the meta-analysis. LSS patients with evidence of RNR (RNR+) were older, WMD 5.7 95% CI [2.2-9.2], p = 0.001, had smaller cross sectional area (CSA) of the stenotic level, WMD -12.2 95% CI [-17.7 to -6.7], p < 0.0001 and longer symptom onset duration, WMD 13.2 95% CI [-0.2-26.7], p = 0.05. The pooled preoperative clinical score in the RNR + group was worse but the difference was not statistically significant, WMD -3.8 95% CI [-7.9 to 0.2], p = 0.07. After decompression surgery RNR + patients had worse clinical scores, -4.7 95% CI [-7.3 to -2.1], p = 0.0004 and lower recovery rates, -9.8 95% CI [-14.8 to -4.7], p = 0.0001. CONCLUSION: There is limited quality evidence that RNR + patients are older, have a longer symptom history and present higher degrees of lumbar stenosis as given by the narrow CSA in comparison to RNR- patients. After decompression surgery RNR + patients have worse clinical scores and lower recovery rates. In view of these results RNR can be seen as a negative prognostic factor in LSS patients.

A retrospective analysis of bone mineral status in patients requiring spinal surgery.

BACKGROUND: Impaired bone quality is associated with poor outcome of spinal surgery. The aim of the study was to assess the bone mineral status of patients scheduled to undergo spinal surgery and to report frequencies of bone mineral disorders. METHODS: We retrospectively analyzed the bone mineral status of 144 patients requiring spinal surgery including bone mineral density by dual-energy X-ray absorptiometry (DXA) as well as laboratory data with serum levels of 25-hydroxyvitamin D (25-OH-D), parathyroid hormone, calcium, bone specific alkaline phosphate, osteocalcin, and gastrin. High-resolution peripheral quantitative computed tomography (HR-pQCT) was additionally performed in a subgroup of 67 patients with T-Score below - 1.5 or history of vertebral fracture. RESULTS: Among 144 patients, 126 patients (87.5%) were older than 60 years. Mean age was 70.1 years. 42 patients (29.1%) had suffered from a vertebral compression fracture. 12 previously undiagnosed vertebral deformities were detected in 12 patients by vertebral fracture assessment (VFA). Osteoporosis was present in 39 patients (27.1%) and osteopenia in 63 patients (43.8%). Only 16 patients (11.1%) had received anti-osteoporotic therapy, while 54 patients (37.5%) had an indication for specific anti-osteoporotic therapy but had not received it yet. The majority of patients had inadequate vitamin D status (73.6%) and 34.7% of patients showed secondary hyperparathyroidism as a sign for a significant disturbed calcium homeostasis. In a subgroup of 67 patients, severe vertebral deformities were associated with stronger deficits in bone microarchitecture at the distal radius compared to the distal tibia. CONCLUSIONS: This study shows that bone metabolism disorders are highly prevalent in elderly patients scheduled for spinal surgery. Vertebral deformities are associated with a predominant deterioration of bone microstructure at the distal radius. As impaired bone quality can compromise surgical outcome, we strongly recommend an evaluation of bone mineral status prior to operation and anti-osteoporotic therapy if necessary.

Incidental durotomy in spine surgery: first aid in ten steps.

INTRODUCTION: Incidental durotomy (ID) is the most common complication of spine surgery. Revision procedures, ossification of the yellow ligament, or synovial cysts are well-known risk factors. The size, shape, and severity of ID are unpredictable, ranging from a pinpoint hole to a several centimeters large dural laceration with transected fibers following the slippage of a cutting burr. Furthermore, the occurrence of ID is always unexpected. Intra-operative management is often based on a steep learning curve rather than a structured scheme. PURPOSE: To provide an intra-operative ten-step closure technique (10ST) for IDs of varying severity. METHODS: A database of 4020 consecutive surgeries for lumbar degenerative disease over the past 4 years was searched for ID. The records of 176 patients were analyzed. Two dural repair techniques were compared: the "individual" technique (InT) and the 10ST. RESULTS: The overall prevalence of ID was 4.4%. The prevalence was lowest in virgin micro-discectomies (1.7%) and ranged from 3.6% in decompression for spinal canal stenosis up to 14.5% in revision procedures. All surgeries were performed with the aid of a microscope. Among 107 primary surgeries, the InT achieved a single-stage closure of the ID in 96 procedures (89.7%). Among 20 virgin surgeries, the 10ST was successful in all cases (P = 0.21). Among 42 re-do procedures following failed attempts to stop cerebrospinal fluid (CSF) leakage, the InT achieved single-stage closure in 36 procedures (85.7%). The 10ST was successful in all 26 cases (P = 0.03). The follow-up was 1 year. CONCLUSIONS: The 10ST should be considered for successful single-stage closure in primary repair of ID.

Lumbar spinal stenosis: prognostic factors for bilateral microsurgical decompression using a unilateral approach.

OBJECTIVE: We describe a prospective cohort study that investigated the effectiveness of microsurgical bilateral decompression using unilateral laminotomy for lumbar spinal stenosis and assessed the factors influencing the outcome. METHODS: A total of 165 consecutive patients underwent decompression for lumbar spinal stenosis. They were divided into 3 age groups: A (<65 years), B (65-75 years), and C (>75 years). Further classification was performed according to body mass index (BMI): BMI 1 (<26), BMI 2 (26-30), and BMI 3 (>30), anesthesiological risk factors (American Society of Anesthesiologists), and the number of levels decompressed. The outcome was monitored by an independent observer at 1 week, 3 months, and 1 year after surgery. The following parameters were evaluated: pain (visual analog scale and analgesic consumption), functional improvement (Neurogenic Claudication Outcome Score), and walking performance, defined as walking distance x speed (treadmill). RESULTS: One week after surgery, pain decreased in 85.9% of patients, and a comparison of the pre- and postoperative use of analgesics showed that 38% of nonopioid use and 74% of opioid use were discontinued, whereas nonsteroidal anti-inflammatory drug consumption increased 13%. One year after surgery, pain remained decreased in 83.9% of patients, Neurogenic Claudication Outcome Score increased in 90.3% of patients, and walking performance improved in 92.2% of patients. BMI greater than 30 was the only negative prognostic factor for pain reduction (P = 0.012) and Neurogenic Claudication Outcome Score improvement (P = 0.019). Surprisingly, patients who underwent multilevel decompression benefitted more from surgery than those who underwent single-level decompression. CONCLUSION: Microsurgical bilateral decompression using unilateral laminotomy is an effective surgical option for lumbar spinal stenosis, even in high-risk patients with multilevel stenosis.

The translaminar approach to lumbar disc herniations impinging the exiting root.

OBJECTIVE: We undertook a prospective, non-randomized study on the translaminar approach for the treatment of cephalad extruded disc fragments impinging the exiting root. METHODS: Between May 2000 and July 2004, 104 patients (59 men)-presenting with upper lumbar root compression in 74% of the cases -underwent a translaminar approach. The mean age was 57 years (range, 27-80 yr). The lamina was approached either through the conventional subperiosteal route or via a muscle splitting access. Mostly intraforaminal disc fragments were removed through a translaminar hole 10 mm in diameter, and the disc space was cleared in cases of evident perforation of the annulus. Follow-up examinations were performed by an independent observer at 1 and 6 weeks; 3, 6, and 12 months; and once yearly thereafter (mean follow-up period, 32 mo). RESULTS: Extruded (61%) or subligamentous (39%) disc fragments were found intra-operatively. Laminae L4 (44%) and L5 (26%) were mostly involved. In eight cases, the translaminar hole was enlarged to a conventional laminotomy. In 13 patients, the disc space was cleared. The outcomes according to the Macnab criteria were excellent (67%), good (27%), fair (5%), and poor (1%). The incidence of recurrent disc herniations was 7%. Functional radiography performed in the first 20 patients 6 months after surgery and an additional 12 patients complaining of postsurgical back pain excluded any instability. CONCLUSION: The translaminar approach is recommended in disc herniations encroaching the exiting root, as an alternative to the conventional interlaminar route.

Lumbar microdiscectomy: subperiosteal versus transmuscular approach and influence on the early postoperative analgesic consumption.

Conventional lumbar microdiscectomy requires subperiosteal dissection of the muscular and tendineous insertions from the midline structures. This prospective, randomized, single center trial aimed to compare a blunt splitting transmuscular approach to the interlaminar window with the subperiosteal microsurgical technique. Two experienced surgeons performed first time lumbar microdiscectomy on 125 patients. The type of approach and retractor used was randomized and both patients and evaluator were blinded to it. In 59 patients a speculum-counter-retractor was inserted through a subperiosteal (SP) route and in 66 patients an expandable tubular retractor was introduced via a transmuscular (TM) approach. In both groups the mean age was 51 years, the male gender prevalent (61%) and the distribution of the operated levels was similar. The outcome measures were VAS for back and leg pain, ODI and the postoperative analgesic consumption was scored by the WHO 3-class protocol. A postsurgical VAS (0-1) was defined as excellent, VAS (2-4) as satisfactory result. In this study the patients scored from 1 to 3 points daily according to the class of drugs taken. Furthermore, a 1/3 point (class 1), 2/3 point (class 2) and 1 point (class 3) was added for each on-demand drug intake. Recovery from radicular pain was excellent (SP 68%, TM 76%) or satisfactory (SP 23%, TM 21%). Recovery from back pain was excellent (SP 58%, TM 59%) or satisfactory (SP 37%, TM 37%). Postoperative mean improvement ODI was: SP 29% and TM 31%. Postoperative mean analgesic intake: SP 4.8 points, TM 2.6 points (P = 0.03). Lumbar microdiscectomy improves pain and ODI irrespective of the type of approach and retractor used. However, the postsurgical analgesic consumption is significantly less if a tubular retractor is inserted via a transmuscular approach.

The impact of esophagus retraction on early dysphagia after anterior cervical surgery: does a correlation exist?

STUDY DESIGN: Prospective study of 92 patients who underwent anterior cervical surgery. Intraoperative esophagus retraction and postoperative dysphagia were recorded and evaluated. OBJECTIVE: Early dysphagia after anterior cervical discectomy and fusion is an underestimated side effect. The aim of this study was to investigate whether postoperative swallowing disturbances correlate with the amount of intraoperative retraction of the pharynx/esophagus wall measured during the procedure. SUMMARY OF BACKGROUND DATA: The anterior approach to the cervical spine is a routinely used and, in general, safe procedure. A recent prospective study focused on the underreported side effect of postoperative dysphagia, with an incidence of up to 50% at 1 month and 12.5% at 12 months. The etiology of postoperative dysphagia is not known in detail. METHODS: An online pressure transducer between the retractor and pharynx/esophagus recorded the epi-esophageal pressure in 92 patients. In 31 patients, a transducer was additionally inserted into the pharynx/esophagus in order to measure the endo-esophageal pressure. The patients rated swallowing difficulty during the first postoperative 5 days using a 10-point score. A control group of 32 lumbar surgery patients was also evaluated for swallowing disturbances. RESULTS: Mean epi-esophageal pressure after retractor opening was 76.3 mm Hg, and mean endo-esophageal pressure was 16.3 mm Hg. An adjustment to 75% and 76%, respectively, of the initial value occurred within the first hour. Of patients, 49.3% complained of swallowing disturbances. There was a significant prevalence of the female gender. No correlation between the amount of retraction and postoperative dysphagia was observed. CONCLUSIONS: A correlation between intraoperative pharynx/esophagus retraction and postoperative swallowing disturbances could not be confirmed. The cause of the prevalence of the female gender is unknown. However, the absence of impaired deglutition in the control group suggests that a local phenomenon must be causative of swallowing disturbances following anterior cervical discectomy and fusion.

Intraoperative measurement of pharynx/esophagus retraction during anterior cervical surgery. Part II: perfusion.

Early postoperative dysphagia after anterior cervical surgery is a well-known phenomenon with so far unknown etiology. We hypothesised that direct pressure induced by the medial retractor blade on pharynx/esophagus mucosal wall leads to local ischemia. Subsequently postoperative hyperemia and swelling of the pharynx/esophagus may result in swallowing disturbance. To prove the hypothesis local blood flow inside the pharynx/esophagus wall during anterior cervical surgery was measured using a laser Doppler (LD) perfusion monitor unit. Fifteen patients underwent standard anterior cervical discectomy and fusion (ACDF). The LD probe was placed underneath the medial retractor blade in order to gain information at the maximum point of pressure applied onto the pharynx/esophagus wall. Local perfusion was measured prior to retractor opening (5 min), during spreading of the retractor and after its closure (5 min). Perfusion was measured semiquantitatively in perfusion units (PU). Local perfusion ranged from 30 to 210 PU (mean 107) prior to retractor opening, from 7 to 60 PU (mean 30) with open retractor and from 15 to 280 PU (mean 117) after retractor closure. In all 15 patients the open retractor led to hypoperfusion ranging from 21 to 93% compared to the baseline level. In seven patients a reactive hyperemia at the end of the procedure was detected (32-89% compared to baseline level). In four patients after hypoperfusion during spreading of the retractor the baseline levels were reached again and in four patients perfusion remained diminished even after retractor closure. To best of our knowledge, this is the first report on intraoperative measurement of local perfusion of the pharynx/esophagus wall during anterior cervical surgery. Diminished local perfusion was observed in all patients during spreading of the retractor and post-procedure hyperemia was recorded in 46% of the patients. The local ischemia of the pharynx/esophagus wall may be a crucial step in the development of postoperative dysphagia.

Intraoperative measurement of pharynx/esophagus retraction during anterior cervical surgery. Part I: pressure.

Temporary dysphagia after anterior cervical discectomy (ACD) is common. However, its mechanism is poorly understood. Pressure induced by retractor blades onto pharynx/esophagus were measured intraoperatively in order to gain more information regarding traumatization of the pharynx/esophagus wall. Thirty-one patients underwent anterior cervical discectomy and fusion (ACDF) for degenerative disc disease. An online pressure transducer was applied to the rear side of the medial retractor blade (epi-esophageal-pressure, epi-P) and a cylindric, inflatable transducer was preoperatively inserted into the pharynx/esophagus under fluoroscopic guidance at the level to be operated on (endo-esophageal-pressure, endo-P). Pressure values were recorded continuously during the operation. Mean arterial pressure (MAP) and endotracheal cuff pressure (ETCP) were recorded additionally. An in vitro model was developed in order to analyze the impact of the retractor blade design onto the epi-esophageal-pressure. Mean epi-P before and following adequate retractor opening for exposure of the disc space was 58.3 and 92.7 mmHg. Thirty, 60 and 90 min later the epi-P decreased to 79, 70 and 66%, respectively. Mean basal endo-P was 9.8 mmHg and increased to 20.6 mmHg after retractor placement. Thirty, 60 and 90 min later the endo-P decreased to 80, 71 and 62%, respectively. The mean MAP was 76 mmHg and the ECTP was adjusted to 25 mmHg during the procedures. In the in vitro model retraction pressure correlated inversely with the contact area between visceral wall and retractor blade. During ACDF the retraction pressure onto the pharyngeal/esophageal wall exceeds MAP and even more the mucosal perfusion pressure of 25 mmHg. Over time the pharynx/esophageal wall adapts to the applied pressure induced by the retractor blade. The contact area between them influences the retraction pressure.

August 2004: 64-year-old man with intermittent paresthesia of the abdomen and of the legs.

A 64-year-old-man had a 2-year history beginning with a sense of abdominal "constriction." Additional slowly rising symptoms, such as tingling of the legs, mild gait ataxia and painful micturition, led to MRI investigation of the spinal cord. A fusiform enlargement of the cord extending from T5 to T8 was shown. The space occupying lesion infiltrated diffusely the spinal cord. A contrast medium enhancing exophytic tumor pellet was approached via a 2-level laminoplasty and resected. Biopsies were taken from different exophytic tumor areas whereas the intramedullary part was spared. The histologic examination confirmed the typical pattern of a pilocytic astrocytoma in all specimens. In our surgical experience with 226 intramedullary tumors and with 117 patients affected by intracranial pilocytic astrocytoma this case is unique because of its combination of tumor location, growth pattern and age of the patient.

Microsurgical excision of symptomatic sacral perineurial cysts: a study of 15 cases.

BACKGROUND: The widespread use of magnetic resonance imaging (MRI), now the first line investigation for back and leg pain, reveals cystic sacral lesions more often than myelography did in the past. There is agreement that symptomatic perineurial sacral cysts should be treated surgically. However, it is still debated whether the preference should be given to the curative option, consisting of excision of the cyst with duraplasty, or to drainage of the cyst to relieve symptoms. In this retrospective study the efficacy of microsurgical cyst resection with duraplasty is evaluated. METHODS: In 15 patients presenting with pain and neurologic deficits, myelography and/or MRI detected sacral cysts. The clinical features suggested that the space-occupying lesions caused the disturbances. Microsurgical excision of the cyst along with duraplasty or plication of the cyst wall was performed in all the cases. Postoperative care included bed rest and CSF drainage for several days. RESULTS: In 13 out of 15 patients the preoperative radicular pain disappeared after surgery. The 2 patients with motor deficits and the 6 patients with bladder dysfunction recovered completely. In all except 1 of the 10 patients complaining of sensory disturbances a significant improvement was achieved. No complications were observed. CONCLUSION: Microsurgical excision of the cyst combined with duraplasty or plication of the cyst wall is an effective and safe treatment of symptomatic sacral cysts and, in the view of the authors, the method of choice.

Narcotrend, bispectral index, and classical electroencephalogram variables during emergence from propofol/remifentanil anesthesia.

UNLABELLED: The aim of this study was to investigate modern and classical electroencephalographic (EEG) variables in response to remifentanil and propofol infusions. We hypothesized that modern EEG variables may indicate the effects of propofol but not of remifentanil. Twenty-five patients were included in the study after the end of elective spine surgery without any surgical stimulation. Baseline values were defined with remifentanil 0.3 microg. kg(-1). min(-1) and target-controlled infusion of propofol 3.0 microg/mL. EEG changes were evaluated 1, 3, 5, 7, and 9 min after the stop of remifentanil infusion, followed by a step-by-step reduction (0.2 microg/mL) every 3 min of target-controlled infusion propofol. Narcotrend (NT; classifying EEG stages from awake to deep anesthesia), bispectral index (BIS), EEG spectral frequency bands (%), 50% (Median) and 95% percentiles (spectral edge frequency), mean arterial blood pressure, heart rate, and oxygen saturation were detected at every time point. The end of remifentanil application resulted in significant increases in %alpha, spectral edge frequency, mean arterial blood pressure, and %theta and decreases in %delta (P < 0.05). NT, BIS, Median, heart rate, and oxygen saturation were unchanged. Decreases in propofol concentration were associated with statistically significant increases in NT and BIS (P < 0.05). Thus, the sedative-hypnotic component of propofol could be estimated by modern EEG variables (NT and BIS), whereas the analgesic component provided by remifentanil was not indicated. However, during conditions without surgical stimulation, neither NT nor BIS provided an adequate assessment of the depth of anesthesia when a remifentanil infusion was used. IMPLICATIONS: We investigated modern and classical electroencephalographic (EEG) variables during emergence from propofol/remifentanil anesthesia. Modern EEG variables indicate changes of infusion in propofol, but not in remifentanil. Thus, modern EEG variables did not provide an adequate assessment of depth of anesthesia when remifentanil was used.

A composite bone graft substitute for anterior cervical fusion: assessment of osseointegration by quantitative computed tomography.

STUDY DESIGN: An ongoing prospective nonrandomized trial was conducted with 146 patients who underwent anterior cervical fusion with a bone graft substitute. The results for 78 patients followed up a minimum of 2 years are reported by an independent observer. OBJECTIVE: To investigate the clinical efficacy and osseointegration of the implant. SUMMARY OF BACKGROUND DATA: Most of the cervical cages provide an immediate load-bearing capacity, but not necessarily a solid fusion. The bony ingrowth can hardly be evaluated by flexion-extension plain radiographs, especially if a part of the implant is made of titanium. METHODS: The composite bone graft substitute consists of a rectangular fenestrated titanium cage filled with a highly porous hydroxyapatite cylinder soaked with bone marrow aspirated from a vertebra. Altogether, 102 implants were inserted for anterior cervical fusion. The bone ingrowth was measured in 50 patients by quantitative computed tomography of the implant and the adjacent vertebrae after 1 week, then 6 and 12 months after surgery. The investigation was repeated in 24 randomly selected patients 24 months after surgery. RESULTS: The surgery benefited 42 of 48 patients with myelopathy, 27 of 28 patients with radiculopathy, and both patients with anterior horn cell syndrome. No graft substitute-related complications were observed, and no revision surgery was performed. Six months after surgery, quantitative computed tomography showed up to a 14% increase in the hydroxyapatite mass in the core of the implant, which was statistically significant (P < 0.001). At 1 year, the newly formed hydroxyapatite mass increased to 23%, and in 2 years reached 24%. CONCLUSIONS: The composite implant is effective as a bone graft substitute, providing immediate load-bearing capacity, an osteoconductive scaffold, and osteoinductive potency. After surgery, the increase in hydroxyapatite radiodensity was apparent in plain computed tomography scans and confirmed to be significant by quantitative computed tomography.