Significance of surgical first assistant expertise for surgical site infection prevention: Propensity score matching analysis.

Surgical site infection (SSI) is one of the most common postoperative complications in patients undergoing major operations, such as spinal fusion surgery, and a major contributor to patient morbidity and mortality. SSI is considered the most preventable type of infection; however, the risk of SSI is multifactorial. This study aimed to determine the extent to which the expertise of the surgical first assistant (SFA) affected SSI rates. We retrospectively reviewed 528 patients at a single institution who underwent lumbar spine fusion surgery via the posterior approach performed by a single surgeon between January 2012 and May 2020. The SFAs participating in the surgeries were classified into 2 groups: a certified neurosurgery specialist and relatively less experienced neurosurgery resident trainees. To reduce potential selection bias and confounding factors, propensity score matching was performed between the 2 groups. In 170 of the 528 lumbar spine fusion surgeries, the SFA was a certified neurosurgery specialist. In the other 358 surgeries, the SFA was a resident trainee. Seventeen patients met the SSI criteria. The SSI rate was significantly different between the 2 groups (0.6% (1 patient) and 4.5% (16 patients) in the certified specialist and resident trainee groups, respectively; P = .02). After propensity score matching, 170 paired patients were selected. After adjusting for confounding factors, SFAs that were certified neurosurgery specialists were associated with a lower likelihood of SSI (adjusted OR 0.09; 95% CI, 0.01 to 0.79; P = .029) than SFAs that were neurosurgery residents. A higher level of SFA expertise was significantly associated with a lower overall SSI rate in lumbar spine fusion surgeries. It is difficult to predict the incidence of SSI; however, this finding suggests the importance of SFA expertise in preventing SSI.

The serpentine pattern on MRI as an early prognostic factor after fusion for lumbar spinal stenosis.

This study aimed to determine the relationship between the serpentine pattern nerve roots (SNR) and prognosis after lumbar fusion for lumbar spinal stenosis (LSS) by comparing clinical outcomes in patients with or without a serpentine pattern. LSS patients with neurological symptoms often present with SNRs. Several studies have shown that LLS symptoms are worse in patients with SNRs. However, the relationship between SNR and outcome after spinal fusion surgery has not yet been established. A total of 332 patients who underwent spinal fusion surgery between January 1, 2010, and December 31, 2019, were enrolled. Patients were divided into those with a serpentine pattern (S group) and those without a serpentine pattern (N group). The prognosis of the 2 groups was compared using visual analog scale (VAS), Oswestry disability index, claudication distance, medication dose for leg dysesthesia, and glucose tolerance. A total of 113 patients had a serpentine pattern, while the remaining 219 did not. Symptom duration and presence of diabetes mellitus were significantly different between the 2 groups (N = 25.4, S = 32.6, P < .05). Changes in the VAS score for lower extremity pain between the 2 groups at 1 year after surgery showed that patients without a serpentine pattern had significantly better outcomes than those with a serpentine pattern (N: 2.7 ±â€…1.1 vs S: 4.1 ±â€…1.3; P < .001), despite the score change at 1 month showing no difference (N: 3.5 ±â€…0.9 vs S: 3.8 ±â€…1.0; P = .09). SNRs on MRI are more prevalent in diabetic patients and are a negative prognostic factor in lumbar fusion surgery for LSS. Our insights may help physicians decide the optimal surgical plan and predict the postoperative prognosis of patients with LSS.

Difference in the Cobb Angle Between Standing and Supine Position as a Prognostic Factor After Vertebral Augmentation in Osteoporotic Vertebral Compression Fractures.

OBJECTIVE: We retrospectively analyzed patients with osteoporotic vertebral compression fracture (OVCF) undergoing vertebral augmentation to compare the Cobb angle changes in the supine and standing positions and the clinical outcomes. METHODS: We retrospectively extracted the data of OVCF patients who underwent vertebral augmentation. Back pain was assessed using a visual analogue scale (VAS). Supine and standing radiographs were assessed before treatment to determine the Cobb angle and compression ratio. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff to predict favorable outcomes after vertebral augmentation. RESULTS: A total of 249 patients were included. We observed a statistically significant increase in the VAS score change with increasing Cobb angle and compression ratio (p < 0.001), and multivariate logistic regression analysis showed that a difference in the Cobb angle (odds ratio [OR], 1.27) and compression ratio (OR, 1.12) were the independent risk factors for predicting short-term favorable outcomes after vertebral augmentation. In addition, we found that the difference in the Cobb angle (OR, 1.05) was the only factor for predicting midterm favorable outcomes after vertebral augmentation. The optimal cutoff value of the difference in the Cobb angle for predicting midterm favorable outcomes was 35.526°. CONCLUSION: We found that the midterm clinical outcome after vertebral augmentation was better when there was a difference of approximately 35% or more in the Cobb angle between the standing and supine positions. Surgeons should pay attention to the difference in the Cobb angle depending on the posture when deciding to perform vertebral augmentation in patients with OVCFs.

Influence of Triggering Events on the Occurrence of Spontaneous Intracranial Hemorrhage : Comparison of Non-Lesional Spontaneous Intraparenchymal Hemorrhage and Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Spontaneous intracranial hemorrhage is a life-threatening disease, and non-lesional spontaneous intraparenchymal hemorrhage (nIPH) and aneurysmal subarachnoid hemorrhage (aSAH) are the leading causes of spontaneous intracranial hemorrhage. Only a few studies have assessed the association between prior physical activity or triggering events and the occurrence of nIPH or aSAH. The purpose of this study is to investigate the role of specific physical activities and triggering events in the occurrence of nIPH and aSAH. METHODS: We retrospectively reviewed 824 consecutive patients with spontaneous intracranial hemorrhage between January 2010 and December 2018. Among the 824 patients, 132 patients were excluded due to insufficient clinical data and other etiologies of spontaneous intracranial hemorrhage. The medical records of 692 patients were reviewed, and the following parameters were assessed : age, sex, history of hypertension, smoking, history of stroke, use of antiplatelet or anticoagulation agents, season and time of onset, physical activities performed according to the metabolic equivalents, and triggering event at onset. Events that suddenly raised the blood pressure such as sudden postural changes, defecation or urination, sexual intercourse, unexpected emotional stress, sauna bath, and medical examination were defined as triggering events. These clinical data were compared between the nIPH and aSAH groups. RESULTS: Both nIPH and aSAH most commonly occurred during non-strenuous physical activity, and there was no significant difference between the two groups (p=0.524). Thirty-two patients (6.6%) in the nIPH group and 39 patients (8.1%) in the aSAH group experienced triggering events at onset, and there was a significant difference between the two groups (p=0.034). The most common triggering events were defecation or urination in both groups. CONCLUSION: Specific physical activity dose no affect the incidence of nIPH and aSAH. The relationship between the occurrence of intracranial hemorrhage and triggering events is higher in aSAH than nIPH.

Phenol-Soluble Modulin-Mediated Aggregation of Community-Associated Methicillin-Resistant Staphylococcus Aureus in Human Cerebrospinal Fluid.

Phenol-soluble modulins (PSMs) are major determinants of Staphylococcus aureus virulence and their increased production in community-associated methicillin-resistant S. aureus (CA-MRSA) likely contributes to the enhanced virulence of MRSA strains. Here, we analyzed the differences in bacterial cell aggregation according to PSM presence in the specific human cerebrospinal fluid (CSF) environment. CSF samples from the intraventricular or lumbar intrathecal area of each patient and tryptic soy broth media were mixed at a 1:1 ratio, inoculated with WT and PSM-deleted mutants (Δpsm) of the CA-MRSA strain, USA300 LAC, and incubated overnight. Cell aggregation images were acquired after culture and image analysis was performed. The cell aggregation ratio in WT samples differed significantly between the two sampling sites (intraventricular: 0.2% vs. lumbar intrathecal: 6.7%, p < 0.001). The cell aggregation ratio in Δpsm samples also differed significantly between the two sampling sites (intraventricular: 0.0% vs. lumbar intrathecal: 1.2%, p < 0.001). Division of the study cases into two groups according to the aggregated area ratio (WT/Δpsm; group A: ratio of ≥ 2, group B: ratio of < 2) showed that the median aggregation ratio value differed significantly between groups A and B (5.5 and 0, respectively, p < 0.001). The differences in CSF distribution and PSM presence within the specific CSF environment are significant factors affecting bacterial cell aggregation.

Transvenous Embolization of Dural Carotid Cavernous Fistula through the Supraorbital Vein.

We describe a case of transvenous embolization through the dilated supraorbital vein to treat a dural carotid cavernous fistula. The approach through the common facial vein or direct access of the superior ophthalmic vein is a commonly used route to the superior ophthalmic vein when the approach via the inferior petrosal sinus is unavailable. In rare cases, the dilated supraorbital vein provides an alternative route and we discuss the technical details.

Risk Factors and Preoperative Risk Scoring System for Shunt-Dependent Hydrocephalus Following Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: Shunt-dependent hydrocephalus (SdHCP) is a well-known complication of aneurysmal subarachnoid hemorrhage (SAH). The risk factors for SdHCP have been widely investigated, but few risk scoring systems have been established to predict SdHCP. This study was performed to investigate the risk factors for SdHCP and devise a risk scoring system for use before aneurysm obliteration. METHODS: We reviewed the data of 301 consecutive patients who underwent aneurysm obliteration following SAH from September 2007 to December 2016. The exclusion criteria for this study were previous aneurysm obliteration, previous major cerebral infarction, the presence of a cavum septum pellucidum, a midline shift of >10 mm on initial computed tomography (CT), and in-hospital mortality. We finally recruited 254 patients and analyzed the following data according to the presence or absence of SdHCP : age, sex, history of hypertension and diabetes mellitus, Hunt-Hess grade, Fisher grade, aneurysm size and location, type of treatment, bicaudate index on initial CT, intraventricular hemorrhage, cerebrospinal fluid drainage, vasospasm, and modified Rankin scale score at discharge. RESULTS: In the multivariate analysis, acute HCP (bicaudate index of ≥0.2) (odds ratio [OR], 6.749; 95% confidence interval [CI], 2.843-16.021; p=0.000), Fisher grade of 4 (OR, 4.108; 95% CI, 1.044-16.169; p=0.043), and an age of ≥50 years (OR, 3.938; 95% CI, 1.375-11.275; p=0.011) were significantly associated with the occurrence of SdHCP. The risk scoring system using above parameters of acute HCP, Fisher grade, and age (AFA score) assigned 1 point to each (total score of 0-3 points). SdHCP occurred in 4.3% of patients with a score of 0, 8.5% with a score of 1, 25.5% with a score of 2, and 61.7% with a score of 3 (p=0.000). In the receiver operating characteristic curve analysis, the area under the curve (AUC) for the risk scoring system was 0.820 (p=0.080; 95% CI, 0.750-0.890). In the internal validation of the risk scoring system, the score reliably predicted SdHCP (AUC, 0.895; p=0.000; 95% CI, 0.847-0.943). CONCLUSION: Our results suggest that the herein-described AFA score is a useful tool for predicting SdHCP before aneurysm obliteration. Prospective validation is needed.

Brain Abscess Showing a Lack of Restricted Diffusion and Successfully Treated with Linezolid.

A 59-year-old patient with a history of hepatocellular carcinoma presented with decreased consciousness and left hemiparesis. A rim-enhanced mass lesion without diffusion restriction was observed in contrast-enhanced MRI including diffusion-weighted imaging. Based on these findings, metastatic brain tumor was suspected. However, brain abscess (BA) was diagnosed after multiple bacterial colonies were observed in aspiration biopsy. Initial conventional antibiotic treatment including vancomycin had failed, so linezolid was used as second-line therapy. As a result, infection signs and clinical symptoms were resolved. We report a case with atypical imaging features and antibiotic susceptibility of a BA in an immunocompromised patient undergoing chemotherapy.

Bone Flap Resorption Following Cranioplasty with Autologous Bone: Quantitative Measurement of Bone Flap Resorption and Predictive Factors.

OBJECTIVE: To quantitatively measure the degree of bone flap resorption (BFR) following autologous bone cranioplasty and to investigate factors associated with BFR. METHODS: We retrospectively reviewed 29 patients who underwent decompressive craniectomy and subsequent autologous bone cranioplasty between April 2005 and October 2014. BFR was defined as: 1) decrement ratio ([the ratio of initial BF size/craniectomy size]-[the ratio of last BF/craniectomy size]) >0.1; and 2) bone flap thinning or geometrical irregularity of bone flap shape on computed tomographic scan or skull plain X-ray. The minimal interval between craniectomy and cranioplasty was one month and the minimal follow-up period was one year. Clinical factors were compared between the BFR and no-BFR groups. RESULTS: The time interval between craniectomy and cranioplasty was 175.7±258.2 days and the mean period of follow up was 1364±886.8 days. Among the 29 patients (mean age 48.1 years, male: female ratio 20: 9), BFR occurred in 8 patients (27.6%). In one patient, removal of the bone flap was carried out due to severe BFR. The overall rate of BFR was 0.10±0.11 over 3.7 years. Following univariate analysis, younger age (30.5±23.2 vs. 54.9±13.4) and longer follow-up period (2204.5±897.3 vs. 1044.1±655.1) were significantly associated with BFR (p=0.008 and 0.003, respectively). CONCLUSION: The degree of BFR following autologous bone cranioplasty was 2.7%/year and was associated with younger age and longer follow-up period.

Impact of Time Interval between Trauma Onset and Burr Hole Surgery on Recurrence of Late Subacute or Chronic Subdural Hematoma.

OBJECTIVE: Although subdural hematoma (SDH) is commonly treatable by burr hole surgery in the late subacute or chronic stage, there is no clear consensus regarding appropriate management and exact predictive factors for postoperative recurrence also remain unclear. The aim of this study was to evaluate risk factors associated with recurrence of SDH that requires burr hole surgery in the late subacute or chronic stage. We also identified the appropriate timing of surgery for reducing the recurrence. METHODS: We retrospectively reviewed 274 patients with SDH in the late subacute or chronic stage treated with burr hole surgery in our hospital between January 2007 and December 2014. Excluding patients with acute intracranial complications or unknown time of trauma onset left 216 patients included in the study. RESULTS: Of 216 patients with SDH in the late subacute or chronic stage, recurrence was observed in 36 patients (16.7%). The timing of the operation in patients with late subacute stage (15-28 days) resulted in a significant decrease in recurrence (RR, 0.33; 95% CI, 0.17-0.65; p=0.001) compared to chronic stage (>28 days). Otherwise, no significant risk factors were associated with recurrences including comorbidities and surgical details. CONCLUSION: The results indicated that time from trauma onset to burr hole surgery may be important for decreasing the risk of recurrence. Therefore, unless patients can be treated conservatively without surgery, prompt surgical management is recommended in patients diagnosed as having late subacute or chronic subdural hematoma treatable by burr hole surgery, even when neurological deficits are unclear.

High-Dose Simvastatin Is Effective in Preventing Cerebral Vasospasm after Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study in Korean Patients.

OBJECTIVE: The goal of this study was to assess the effect of high-dose simvastatin on cerebral vasospasm and its clinical outcome after aneurysmal subarachnoid hemorrhage (SAH) in Korean patients. METHODS: This study was designed as a prospective observational cohort study. Its subjects were aneurysmal SAH patients who had undergone aneurysm clipping or coiling. They were assigned to 1 of 3 groups : the 20 mg, 40 mg, and 80 mg simvastatin groups. The primary end-point was the occurrence of symptomatic vasospasm. The clinical outcome was assessed with the modified Rankin Scale (mRS) score after 1 month and 3 months. The risk factors of the development of vasospasm were assessed by logistic regression analysis. RESULTS: Ninety nine patients with aneurysmal SAH were treated and screened. They were sequentially assigned to the 20 mg (n=22), 40 mg (n=34), and 80 mg (n=31) simvastatin groups. Symptomatic vasospasm occurred in 36.4% of the 20 mg group, 8.8% of the 40 mg group, and 3.2% of the 80 mg group (p=0.003). The multiple logistic regression analysis showed that poor Hunt-Hess grades (OR=5.4 and 95% CI=1.09-26.62) and high-dose (80 mg) simvastatin (OR=0.09 and 95% CI=0.1-0.85) were independent factors of symptomatic vasospasm. The clinical outcomes did not show a significant difference among the three groups. CONCLUSION: This study demonstrated that 80 mg simvastatin treatment was effective in preventing cerebral vasospasm after aneurysmal SAH, but did not improve the clinical outcome in Korean patients.

Long-term results of motor cortex stimulation in the treatment of chronic, intractable neuropathic pain.

BACKGROUND/OBJECTIVES: Although motor cortex stimulation (MCS) has been used for more than 20 years in the treatment of chronic neuropathic pain, there is still a debate about the efficacy of MCS. METHODS: To investigate the long-term results and the factors associated with the long-term success of chronic MCS, 21 patients who underwent MCS trial were classified as having central poststroke pain, central pain after spinal cord injury (SCI) and peripheral neuropathic pain, and we investigated the clinical factors associated with long-term success and degree of pain relief. RESULTS: Of the 21 patients, 16 (76.2%) had a successful trial and underwent chronic MCS. In the long-term follow-up (53 ± 39 months), only the diagnosis (central poststroke pain and peripheral neuropathic pain) was associated with long-term success defined as >30% pain relief compared with baseline (p < 0.05, χ(2) test). The difference in pain relief was not significant in patients having SCI pain (p > 0.05, 1-way ANOVA). The other variables did not show any significant influence in the long-term success and degree of pain relief (p > 0.05, 1-way ANOVA). CONCLUSIONS: MCS was more effective in the treatment of chronic neuropathic pain of central poststroke pain and peripheral neuropathic pain types than in the treatment of SCI pain in the long-term follow-up.

Stereotactic mesencephalotomy for cancer - related facial pain.

Cancer-related facial pain refractory to pharmacologic management or nondestructive means is a major indication for destructive pain surgery. Stereotactic mesencephalotomy can be a valuable procedure in the management of cancer pain involving the upper extremities or the face, with the assistance of magnetic resonance imaging (MRI) and electrophysiologic mapping. A 72-year-old man presented with a 3-year history of intractable left-sided facial pain. When pharmacologic and nondestructive measures failed to provide pain alleviation, he was reexamined and diagnosed with inoperable hard palate cancer with intracranial extension. During the concurrent chemoradiation treatment, his cancer-related facial pain was aggravated and became medically intractable. After careful consideration, MRI-based stereotactic mesencephalotomy was performed at a point 5 mm behind the posterior commissure, 6 mm lateral to and 5 mm below the intercommissural plane using a 2-mm electrode, with the temperature of the electrode raised to 80℃ for 60 seconds. Up until now, the pain has been relatively well-controlled by intermittent intraventricular morphine injection and oral opioids, with the pain level remaining at visual analogue scale 4 or 5. Stereotactic mesencephalotomy with the use of high-resolution MRI and electrophysiologic localization is a valuable procedure in patients with cancer-related facial pain.

Simultaneous trial of deep brain and motor cortex stimulation in chronic intractable neuropathic pain.

BACKGROUND/OBJECTIVES: Both motor cortex stimulation (MCS) and deep brain stimulation (DBS) of the ventralis caudalis (Vc) thalamus have been shown to be effective in chronic neuropathic pain, and the modulation of thalamic and thalamocortical activity is regarded as a possible mechanism. Although Vc DBS and MCS have a common analgesic mechanism, the application of MCS and DBS is still considered empirical, and there is no consensus on which method is better. METHODS: We performed a simultaneous trial of thalamic Vc DBS and MCS in 9 patients with chronic neuropathic pain and investigated the results of the stimulation trial and long-term pain relief. RESULTS: Of the 9 patients initially implanted with both DBS and MCS electrodes, 8 (89%) had a successful trial; 6 of these 8 patients (75%) responded to MCS, and the remaining 2 responded to Vc DBS. During the long-term follow-up, the mean numeric rating scale score decreased significantly (p < 0.05). The percentages of pain relief in the chronic MCS group and the chronic DBS group were 37.9 ± 16.5 and 37.5%, respectively, and there was no statistically significant difference (p = 0.157). CONCLUSION: Considering the initial success rate and the less invasive nature of epidural MCS compared with DBS, we think that MCS would be a more reasonable initial means of treatment for chronic intractable neuropathic pain.

Dorsal rhizotomy for pain from neoplastic lumbosacral plexopathy in advanced pelvic cancer.

BACKGROUND: Pain from neoplastic lumbosacral plexopathy is resistant to conventional pain treatment. According to a recent review of destructive procedures for cancer pain, only cordotomy has been reported to play an important role in the treatment of cancer pain. To date, the effectiveness of dorsal rhizotomy, which selectively interrupts pain transmission, has not been shown in neoplastic lumbosacral plexopathy. OBJECTIVES: The present study seeks to find out the effectiveness of selective dorsal rhizotomies for intractable pain from neoplastic lumbosacral plexopathy in terminal pelvic cancer patients. METHODS: Dorsal rhizotomies of the involved segments were performed on 6 cancer patients in whom neuropathic pain from lumbosacral plexus involvement in terminal pelvic cancer had been refractory to other therapies. Clinical efficacy of the procedure was assessed by comparing patient pain ratings and narcotic usage before and after dorsal rhizotomy. RESULTS: Examination of the results indicated a significant reduction in pain ratings as well as a significant reduction in daily narcotic use. No adverse neurological effects were observed and no recurrence of pain from neoplastic lumbosacral plexopathy was noted. CONCLUSIONS: These findings provide corroborating clinical evidence for the effectiveness of selective dorsal root rhizotomy for the intractable pain from lumbosacral plexopathy in terminal pelvic cancer patients.

Significance of intracranial pressure monitoring after early decompressive craniectomy in patients with severe traumatic brain injury.

OBJECTIVE: Early decompressive craniectomy (DC) has been used as the first stage treatment to prevent secondary injuries in cases of severe traumatic brain injury (TBI). Postoperative management is the major factor that influences outcome. The aim of this study is to investigate the effect of postoperative management, using intracranial pressure (ICP) monitoring and including consecutive DC on the other side, on the two-week mortality in severe TBI patients treated with early DC. METHODS: Seventy-eight patients with severe TBI [Glasgow Coma Scale (GCS) score <9] underwent early DC were retrospectively investigated. Among 78 patients with early DC, 53 patients were managed by conventional medical treatments and the other, 25 patients were treated under the guidance of ICP monitoring, placed during early DC. In the ICP monitoring group, consecutive DC on the other side were performed on 11 patients due to a high ICP of greater than 30 mm Hg and failure to respond to any other medical treatments. RESULTS: The two-week mortality rate was significantly different between two groups [50.9% (27 patients) and 24% (6 patients), respectively, p=0.025]. After adjusting for confounding factors, including sex, low GCS score, and pupillary abnormalities, ICP monitoring was associated with a 78% lower likelihood of 2-week mortality (p=0.021). CONCLUSION: ICP monitoring in conjunction with postoperative treatment, after early DC, is associated with a significantly reduced risk of death.

Intractable occipital neuralgia caused by an entrapment in the semispinalis capitis.

Occipital neuralgia is a rare pain syndrome characterized by periodic lancinating pain involving the occipital nerve complex. We present a unique case of entrapment of the greater occipital nerve (GON) within the semispinalis capitis, which was thought to be the cause of occipital neuralgia. A 66-year-old woman with refractory left occipital neuralgia revealed an abnormally low-loop of the left posterior inferior cerebellar artery on the magnetic resonance imaging, suggesting possible vascular compression of the upper cervical roots. During exploration, however, the GON was found to be entrapped at the perforation site of the semispinalis capitis. There was no other compression of the GON or of C1 and C2 dorsal roots in their intracranial course. Postoperatively, the patient experienced almost complete relief of typical neuralgic pain. Although occipital neuralgia has been reported to occur by stretching of the GON by inferior oblique muscle or C1-C2 arthrosis, peripheral compression in the transmuscular course of the GON in the semispinalis capitis as a cause of refractory occipital neuralgia has not been reported and this should be considered when assessing surgical options for refractory occipital neuralgia.

Long-term outcome of gamma knife surgery using a retrogasserian petrous bone target for classic trigeminal neuralgia.

BACKGROUND: Gamma knife surgery (GKS) is the prevailing method for treatment of medically intractable trigeminal neuralgia (TN), although there are some technical differences among radiosurgical centers. We assessed the long-term outcomes of GKS using retrogasserian petrous bone targeting and evaluated factors associated with the clinical outcomes. METHODS: Between December 2003 and June 2009, a total of 91 GKS treatments were performed in 90 patients with classic TN. The surgical target was defined at the anterior portion of the trigeminal nerve, just above the retrogasserian petrous bone. A single 4-mm collimator was used to deliver a median 88.0 Gy (range 75-90 Gy) dose of radiation. FINDINGS: During follow-up, which ranged from 24 to 90 months, 89 patients (97.8 %) reported initial pain relief, 75 (82.4 %) experienced pain control, and 47 (51.6 %) achieved a pain-free state without medications at the last follow-up. Barrow Neurological Institute (BNI) scores of I-III at 2, 3, 4, 5, and 7 years were observed in 84 of 91, 68 of 77, 46 of 53, 33 of 36, 17 of 19, and 7 of 7 patients, respectively. Trigeminal nerve dysfunction was experienced by 34 patients, with 12 having BNI facial numbness scores of III-IV (13.2 %). In all, 14 patients (15.4 %) experienced pain recurrence at a mean 32 months (range 10-62 months) after treatment. The actuarial rates of pain control at 2, 4, and 6 years were 93 %, 88 %, and 79 %, respectively. CONCLUSIONS: Gamma Knife radiosurgery is an efficient option for intractable TN. Our results can help medical practitioners to counsel their patients on the likelihood of achieving successful pain control.

Factors associated with the success of trial spinal cord stimulation in patients with chronic pain from failed back surgery syndrome.

OBJECTIVE: Spinal cord stimulation (SCS) is an effective means of treatment of chronic neuropathic pain from failed back surgery syndrome (FBSS). Because the success of trial stimulation is an essential part of SCS, we investigated factors associated with success of trial stimulation. METHODS: Successful trial stimulation was possible in 26 of 44 patients (63.6%) who underwent insertion of electrodes for the treatment of chronic pain from FBSS. To investigate factors associated with successful trial stimulation, patients were classified into two groups (success and failure in trial). We investigated the following factors : age, sex, predominant pain areas (axial, limb, axial combined with limbs), number of operations, duration of preoperative pain, type of electrode (cylindrical/paddle), predominant type of pain (nociceptive, neuropathic, mixed), degree of sensory loss in painful areas, presence of motor weakness, and preoperative Visual Analogue Scale. RESULTS: There were no significant differences between the two groups in terms of age, degree of pain, number of operations, and duration of pain (p>0.05). Univariate analysis revealed that the type of electrode and presence of severe sensory deficits were significantly associated with the success of trial stimulation (p<0.05). However, the remaining variable, sex, type of pain, main location of pain, degree of pain duration, degree of sensory loss, and presence of motor weakness, were not associated with the trial success of SCS for FBSS. CONCLUSION: Trial stimulation with paddle leads was more successful. If severe sensory deficits occur in the painful dermatomes in FBSS, trial stimulation were less effective.

Neurolysis for meralgia paresthetica.

OBJECTIVE: Meralgia paresthetica (MP) is a syndrome of pain and/or dysesthesia in the anterolateral thigh that is caused by an entrapment of the lateral femoral cutaneous nerve (LFCN) at its pelvic exit. Despite early accounts of MP, there is still no consensus concerning the effectiveness of neurolysis or transaction treatments in the long-term relief for medically refractory patients with MP. We retrospectively analyzed available long-term results of LFCN neurolysis for medically refractory MP in an effort to clarify this issue. METHODS: During the last 7 years, 11 patients who had neurolysis for MP were enrolled in this study. Nerve entrapment was confirmed preoperatively by electrophysiological studies or a positive response to local anesthetic injection. Decompression of the LFCN was performed at the level of the iliac fascia, inguinal ligament, and fascia of the thigh distally. The outcome of surgery was assessed 8 weeks after the procedure followed at regular intervals if symptoms persisted. RESULTS: Twelve decompression procedures were performed in 11 patients over a 7-year period. The average duration of symptoms was 8.5 months (range, 4-15 months). The average follow-up period was 33 months (range, 12-60 months). Complete and partial symptom improvement were noted in nine (81.8%) and two (18.2%) cases, respectively. No recurrence was reported. CONCLUSION: Neurolysis of the LFCN can provide adequate pain relief with minimal complications for medically refractory MP. To achieve a good outcome in neurolysis for MP, an accurate diagnosis with careful examination and repeated blocks of the LFCN, along with electrodiagnosis seems to be essential. Possible variation in the course of the LFCN and thorough decompression along the course of the LFCN should be kept in mind in planning decompression surgery for MP.