Surgical Site Infection 18 Months Following Intrathecal Pump Placement Secondary to an Asymptomatic Bowel Injury.

Surgical site infections following the implantation of intrathecal drug delivery systems typically present during the first 1 to 2 months following surgery. Surgical site infections occurring outside of this window are rare entities and require special attention to identify the source or underlying cause. In this report, we present a case of pump pocket infection 18 months following implantation due to an asymptomatic and unrecognized bowel injury associated with the catheter. This case highlights the need for a thorough evaluation in a patient with suspected infections more than 2 months after surgery to ensure adequate treatment.

Cervical arterial dissection and traumatic myelopathy following yoga: surgical case report.

INTRODUCTION: Cervical spondylosis can predispose patients to central canal stenosis. In this setting, myelopathy through further flattening of the cord from extrinsic compression can be precipitated by relatively minor traumas. Arterial dissection is similarly considered a result of high velocity or momentum during trauma, commonly associated with fractures, cervical hyperflexion, or direct blunt force to the neck. Overall, precautions for both arterial dissection and myelopathy are rarely considered in low-velocity, static activities such as yoga. CASE PRESENTATION: The authors report the case of a 63-year-old man who suffered concurrent cervical myelopathy from multilevel spondylopathy, right vertebral artery dissection, and left cervical carotid artery dissection following a yoga session. Symptomatology consisted of acute onset neck pain, upper extremity sensory paresthesia, worsening gait and balance, and impaired dexterity for several weeks. Cervical MRI was obtained given myelopathic symptoms and revealed spondylosis with compression and T2 signal change at C3-C4. CT angiography of the neck revealed aforementioned dissections without flow limiting stenosis or occlusion. A therapeutic heparin infusion was started preoperatively until the patient underwent C3-C4 anterior cervical discectomy and fusion. Aspirin and Plavix were then started without incidence and the patient had significant but gradual improvement in myelopathic symptoms at 6-week follow-up. DISCUSSION: The static yet intensive poses associated with yoga present a rare etiology for arterial dissection and myelopathy, but patients with persistent and progressive symptoms should be screened with the appropriate imaging modality. Cervical decompression should be expedited before initiating an antiplatelet medication.

Cervicomedullary junction spinal cord stimulation for head and facial pain.

OBJECTIVE: To review our experience with cervicomedullary junction spinal cord stimulation (SCS), to alleviate head and facial pain. BACKGROUND: There is a dearth of literature regarding the use of spinal cord stimulation for treating head and facial pain. DESIGN: We performed a Boolean search of the electronic medical record (1990-2009) and identified 35 patients (9 men, 26 women) for whom the senior author (J.J.M) trialed paddle lead cervicomedullary junction stimulation (CMJ-S) for intractable head or facial pain. Twenty-five patients (71.4%) had a successful trial with subsequent implantation of SCS hardware and 10 patients (28.6%) experienced a failed trial. Pain syndromes were categorized into diagnostic groups: trigeminal deafferentation pain (TDP), trigeminal neuropathic pain (TNP), occipital pain/neuralgia, post-herpetic neuralgia (PHN), and post-stroke facial pain. Follow-up via structured telephone interview was obtained in 25 patients (71.4%). RESULTS: Among the 25 patients available for follow-up, 16 patients (64%) underwent implantation and 9 patients (36%) had a failed trial of CMJ-S. The mean patient age and length of follow-up was 47.3 years old (20-78 years old) and 53.4 months (2-120 months), respectively. On a 0-10 pain intensity scale (0 being no pain and 10 being the worst degree of pain), a mean pretrial pain level of 9.6 (range 7-10) had been reduced to a mean of 4.8 (0-10) at follow-up. Successful trial and subsequent implantation occurred in 7 patients with TDP (70%), 4 patients with TNP (80%), both patients with PHN (100%), and in the single patient with post-stroke facial pain (100%) but in only 2 patients (28.6%) with occipital neuralgia/pain. At the time of telephone interview, 4 of the implanted patents (25%) had their hardware removed because of loss of effectiveness (3) and infection (1). The other 12 implanted patients (75%) continue to use CMJ-S on a daily basis and insist that it has improved their quality of life. Six current users (50%) of CMJ-S have been able to decrease their use of oral pain medications. Complications in the implanted group included infection (1), uncomfortable paresthesias from breakdown of connecting wire insulation (1), and gradual loss of effectiveness (3). CONCLUSIONS: Our preliminary experience suggests that patients suffering from TDP, TNP, and PHN may respond favorably to CMJ-S whereas patients with occipital neuralgia/pain are rarely palliated by this neuromodulatory approach.

Hemorrhage rates after external ventricular drain placement.

OBJECT: External ventricular drain (EVD) placement is one of the most common neurosurgical procedures performed. Rates and significance of hemorrhage associated with this procedure have not been well quantified. METHODS: All adults who underwent EVD placement at the University of Pittsburgh Medical Center between July 2002 and June 2003 were evaluated for catheter-associated hemorrhage. Patients without postprocedural imaging were excluded. RESULTS: Seventy-seven (41%) of 188 EVDs were associated with imaging evidence of hemorrhage after either placement or removal. Most of these were insignificant, punctate intraparenchymal, or trace subarachnoid hemorrhages (51.9%). Thirty-seven (19.7%) were associated with larger hemorrhages, which were divided into 3 groups according to volume of hemorrhage: 16 patients (8.5%) had < 15 ml of hemorrhage, 20 (10.6%) had hemorrhages of > 15 ml or associated intraventricular hemorrhage, and in 1 case there was a subdural hematoma that required surgical evacuation. No hemorrhages larger than punctate or trace were seen after EVD removal. Hemorrhage was associated with 44.3% of EVDs placed in an intensive care unit compared with 34.8% in EVDs placed in the operating room (p > 0.10). CONCLUSIONS: External ventricular drain placement has a significant risk of associated hemorrhage. However, the hemorrhages are rarely large and almost never require surgical intervention. There is a favorable trend, but no significant risk reduction when EVDs are placed in the operating room rather than the intensive care unit.

Complete Bilateral Brachial Plexus Injury from Rhabdomyolysis and Compartment Syndrome: Surgical Case Report.

BACKGROUND AND IMPORTANCE: Acute bilateral brachial plexus injury is rare and usually a result of traction injury. Immediate operative intervention is reserved for rare cases of ongoing compression of the plexus; the role for acute decompression of the brachial plexus secondary to compartment syndrome has not been previously described. In this report, we describe the technique and role for urgent brachial plexus decompression. CLINICAL PRESENTATION: A 32-yr-old man presented with acute complete bilateral brachial plexus palsy due to focal rhabdomyolysis and brachial plexus compression after a night of excess alcohol and methadone ingestion. He had complete loss of motor and sensory function from C5 to T1, with the exception of partial sensory sparing of the C5 dermatome. Magnetic resonance imaging demonstrated diffuse muscular edema of the supraclavicular and infraclavicular fossae in addition to the pectoralis muscles and the deltoids bilaterally. He underwent urgent surgical decompression of his supraclavicular and infraclavicular fossae with fasciotomies of the pectoral muscles and the anterior deltoids, allowing direct visualization and decompression of the entire brachial plexus resulting in a near-complete functional recovery. CONCLUSION: Neurosurgeons should include brachial plexus compression due to compartment syndrome in the differential diagnosis of patients with acute upper extremity weakness, particularly when associated with prolonged immobilization and/or substance abuse. Prompt surgical decompression should be performed in these patients if imaging and laboratory data suggest compartment syndrome and resultant neurological deficit.

Endoscopic endonasal suturing of dural reconstruction grafts: a novel application of the U-Clip technology. Technical note.

Cerebrospinal fluid (CSF) leakage following endoscopic endonasal skull base resection can be a significant problem. A method for securing tissue grafts is needed. In this paper the authors used an endonasal suturing device to secure the graft reconstruction following endonasal tumor resection. The U-Clip anastomotic device (Medtronic), developed for cardiovascular anastomoses, was used to secure the tissue graft to native dura. A specialized needle driver and hemoclip applier were used for the application and deployment of this device. No suture tying was necessary, facilitating its endonasal application. The graft was successfully secured in its desired position to native dura by using the U-Clip anastomotic device. The patient did not suffer a postoperative CSF leak, and postoperative imaging and endoscopy revealed that the graft was in a good position. There was no complication from the use of the device. The U-Clip anastomotic device can be used as a suture device during endonasal surgery. It may prevent tissue graft migration and help prevent CSF leakage.

Minimally invasive endoscopic-assisted posterior thoracic sympathectomy.

Palmar hyperhidrosis is a disorder of the autonomic nervous system characterized by excessive perspiration of the palms, but may involve other body parts as well. Traditional posterior approaches have been performed less often in favor of less invasive thoracoscopic sympathectomies, which have a high success rate with low associated morbidity. However, some patients are not candidates for a transthoracic surgery and may need an alternative treatment strategy. In situations in which a posterior approach may be necessary, the authors have developed a minimal access endoscopic-assisted dorsal sympathectomy procedure, applying minimally invasive spine muscle splitting techniques. The authors believe that the development of this technique may help to minimize surgical morbidity associated with the traditional posterior approach by reducing pain, tissue damage, and length of postoperative recovery. This paper is a report on the successful treatment of palmar hyperhidrosis using a minimally invasive posterior technique and describes the surgical approach and outcomes in 2 patients who have been treated in this manner. Two patients underwent minimally invasive endoscopic-assisted posterior thoracic sympathectomy for hyperhidrosis. Both patients experienced relief of their symptoms after surgery with follow-up durations of 32 and 9 months and length of stays of 0.9 and 2.8 days, respectively. One patient suffered a unilateral Horner syndrome and underwent an eyelid lift. The other patient was readmitted to the hospital 2 days after discharge with atelectasis. She was obese and suffered from chronic obstructive pulmonary disease at baseline, which were reasons she opted for a posterior approach. Neither patient suffered a pneumo- or hemothorax. Minimally invasive endoscopic-assisted posterior thoracic sympathectomy can be safely performed for relief of hyperhidrosis. The procedure has risks for the usual complications of sympathectomy. This technique may provide an alternative to thoracoscopic approaches, especially in those patients with pulmonary disease or obesity.

Subacute histopathological features in a case of varicella zoster virus myelitis and post-herpetic neuralgia.

INTRODUCTION: Post-herpetic neuralgia is a crippling complication of varicella zoster virus (VZV) reactivation, also known as zoster disease. In rare cases, VZV spreads to the spinal cord and causes myelitis. There is a paucity of data on spinal cord histopathology in the subacute phase of post-herpetic neuralgia and VZV myelitis. CASE DESCRIPTION: In this report, we present a case of post-herpetic neuralgia in a patient who died 5 weeks after initiation of symptoms. Autopsy limited to the spinal cord revealed severe tissue vacuolization associated with macrophage and lymphocytic infiltration that was most intense in the right posterior horn, corresponding to an area of magnetic resonance imaging (MRI) T2-weighted hyperintensity. There was some extension of the inflammatory response to the ipsilateral posterior column, dorsolateral column, precentral gray matter, and contralateral lateral column. No significant axonal or myelin loss was observed. Nerve roots and meninges were free of significant inflammation. DISCUSSION: Our findings provide histopathological insight into early subacute changes in post-herpetic neuralgia and suggest the involvement of the cord and subsequent macrophage and lymphocyte inflammatory response may lead to pain fiber irritation and the clinical pain syndrome of post-herpetic neuralgia.

Long-term outcomes of intradural cervical dorsal root rhizotomy for refractory occipital neuralgia.

OBJECT Occipital neuralgia (ON) causes chronic pain in the cutaneous distribution of the greater and lesser occipital nerves. The long-term efficacy of cervical dorsal root rhizotomy (CDR) in the management of ON has not been well described. The authors reviewed their 14-year experience with CDR to assess pain relief and functional outcomes in patients with medically refractory ON. METHODS A retrospective chart review of 75 ON patients who underwent cervical dorsal root rhizotomy, from 1998 to 2012, was performed. Fifty-five patients were included because they met the International Headache Society's (IHS) diagnostic criteria for ON, responded to CT-guided nerve blocks at the C-2 dorsal nerve root, and had at least one follow-up visit. Telephone interviews were additionally used to obtain data on patient satisfaction. RESULTS Forty-two patients (76%) were female, and the average age at surgery was 46 years (range 16-80). Average follow up was 67 months (range 5-150). Etiologies of ON included the following: idiopathic (44%), posttraumatic (27%), postsurgical (22%), post-cerebrovascular accident (4%), postherpetic (2%), and postviral (2%). At last follow-up, 35 patients (64%) reported full pain relief, 11 (20%) partial relief, and 7 (16%) no pain relief. The extent of pain relief after CDR was not significantly associated with ON etiology (p = 0.43). Of 37 patients whose satisfaction-related data were obtained, 25 (68%) reported willingness to undergo repeat surgery for similar pain relief, while 11 (30%) reported no such willingness; a single patient (2%) did not answer this question. Twenty-one individuals (57%) reported that their activity level/functional state improved after surgery, 5 (13%) reported a decline, and 11 (30%) reported no difference. The most common acute postoperative complications were infections in 9% (n = 5) and CSF leaks in 5% (n = 3); chronic complications included neck pain/stiffness in 16% (n = 9) and upper-extremity symptoms in 5% (n = 3) such as trapezius weakness, shoulder pain, and arm paresthesias. CONCLUSIONS Cervical dorsal root rhizotomy provides an efficacious means for pain relief in patients with medically refractory ON. In the appropriately selected patient, it may lead to optimal outcomes with a relatively low risk of complications.

Multimodal assessment after surgery for cervical spondylotic myelopathy.

OBJECT: Investigators reporting decompressive surgery to treat patients with cervical spondylotic myelopathy (CSM) have described inconsistent benefits. In the present study the authors used three types of outcomes instruments to assess the results of CSM surgery. METHODS: The authors collected prospective baseline and 6-month follow-up data in a cohort of 62 patients with CSM. Data collection included those pertaining to demographics; symptoms; physical findings; myelopathy severity; health status measured with the Short Form-36; and health values according to the standard gamble, time trade-off, visual analog scale, and willingness to pay. Rank-order methods were used to compare surgical and nonsurgical patients, and multivariate regression techniques adjusting for baseline characteristics were performed to examine the effects of surgery. During the study period, 28 patients underwent surgery, 34 did not, and there were no baseline differences between the two groups in demographics, symptoms, myelopathy scores, health status, or health values (p > or = 0.120 in all domains); there was a greater prevalence of hand intrinsic muscle atrophy (p = 0.035) and Hoffmann sign (p = 0.006) in the surgery-treated group. Neither raw comparisons nor regression analyses showed a consistent surgery-related benefit. There were sporadic associations between worse outcomes and older patients, higher income, Babinski sign, longer duration of CSM symptoms, hand clumsiness, lower-extremity numbness, and multilevel surgery (p < or = 0.049 for all). CONCLUSIONS: Analysis of results obtained in the 62 patients with CSM failed to show a surgery-related benefit despite the use of three classes of outcomes instruments. Patient demographics, symptoms, physical signs, and the surgical approach may explain some of the variation in outcomes in patients with CSM.

Clinical Experience With Continuous Intrathecal Baclofen Trials Prior to Pump Implantation.

OBJECTIVE: To report our clinical experience using continuous intrathecal baclofen (ITB) trials prior to permanent pump implantation. DESIGN: Retrospective chart review. SETTING: An inpatient neurosurgery unit and outpatient physical medicine and rehabilitation clinics. PARTICIPANTS: Fifty-seven patients with refractory spasticity who underwent a continuous ITB trial during the years 2006-2012. METHODS: Patients underwent placement of a temporary intrathecal catheter that was connected to an external pump. A successful trial was defined as a one-level reduction in lower limb modified Ashworth scores in key spastic lower limb muscles identified for each individual patient. Subjective improvement in function or ease of performing functional tasks also were monitored. MAIN OUTCOME MEASURES: Modified Ashworth scores, functional mobility in ambulatory patients only, and the incidence and severity of adverse events during the trial and up to 1 year after implantation. RESULTS: Spasticity significantly decreased during the trial. Average ambulation distance was unchanged, although 34% of ambulatory patients progressed to a less restrictive assistive device by trial completion. Adverse events (AEs) occurred in 26 patients. Minor AEs were seen in 18 patients, with the most common being nausea, transient urinary retention, and headache. Pumps were implanted in 86% of patients; 14% did not receive a pump because of AEs or because goals were not met. Six patients had their pump removed at 12 months for the following reasons: pump malfunctions (3), skin breakdown around the pump (1), infection (1), and expectations not met (1). CONCLUSIONS: Continuous trials via an external catheter could be an option if patients and clinicians desire a comprehensive assessment of systemic and functional effects of ITB before pump implantation. The majority of AEs were minor and resolved spontaneously, and the most effective starting intrathecal dose was determined by pump insertion.

Spinal and Nucleus Caudalis Dorsal Root Entry Zone Lesioning for Chronic Pain: Efficacy and Outcomes.

BACKGROUND: The role for nucleus caudalis (NC) and spinal dorsal root entry zone (DREZ) lesioning in the management of chronic pain emanating from increased electrical activity in the dorsal horn of the spinal cord and brainstem remains largely uncharted. METHODS: All patients who underwent NC and spinal DREZ lesioning by a single surgeon were identified and follow-up was obtained by telephone questionnaires. Patient demographics, surgical details, outcomes, and complications were critically reviewed for all patients identified. RESULTS: Of 83 patients identified, 53 (63.9%) were male. Indications for NC DREZ lesioning included trigeminal neuropathic pain (6), trigeminal deafferentation pain (3), glossopharyngeal or occipital neuralgia (3), post-herpetic neuralgia (3), and trauma (1); for spinal DREZ lesioning, indications included brachial plexus avulsion (20), post-herpetic neuralgia (19), spinal cord injury (11), phantom limb pain (8), pelvic pain (5), and complex regional pain syndrome (4). Pain relief was most significant among patients with trigeminal pain, traumatic brachial plexus avulsion injuries, spinal cord injury, and traumatic phantom limb pain. Mean pain reduction averaged 58.3% at a mean follow-up of 8.3 years. Complications included 3 cases of paresis, 3 cases of neuropathy/radiculopathy, 2 cases of ataxia, 3 general medical conditions (colitis, 2; atelectasis, 1), and 2 cases of persistent incisional site pain. Pain relief lasted an average of 4.3 years. CONCLUSIONS: Spinal and NC DREZ lesioning can provide effective relief in well-selected patients with intractable chronic pain conditions arising from trigeminal pain, spinal cord injury, brachial plexus avulsions, post-herpetic neuralgia, and phantom limb pain.

Low-dose radiotherapy for the inhibition of peridural fibrosis after reexploratory nerve root decompression for postlaminectomy syndrome.

OBJECT: The authors of clinical studies have demonstrated a significant association between the presence of extensive post-lumbar discectomy peridural scar formation and the recurrence of low-back and radicular pain. Low-dose perioperative radiotherapy has been demonstrated to inhibit peridural fibrosis after laminectomy in animal models. The present study was designed to evaluate the clinical efficacy of preoperative irradiation in patients with failed-back surgery syndrome due to peridural fibrosis who underwent reexploration and nerve root decompression. METHODS: Ten patients with symptomatic post-discectomy peridural fibrosis were randomized. Half of the patients underwent 700-cGy external-beam irradiation to the operative site 24 hours prior to reexploration and decompressive treatment of their symptomatic nerve root(s) (treatment group) and the other half underwent reexploration and decompressive treatment without preoperative irradiation (control group). All patients underwent simulated irradiation so neither patient nor surgeon was aware of the patient's group. In all patients the antiadhesion product ADCON-L was placed over the affected nerve root at the time of surgery. Clinical outcome was assessed using the American Association of Neurological Surgeons/Congress of Neurological Surgeons Joint Section Lumbar Disc Herniation Study Questionnaire at baseline, 6 weeks, 3 months, and 1 year follow up. Five men and five women (mean age 42 years) underwent randomization and surgery. Three patients underwent reexploration at L4-5, four at L5-S1, and three at both levels. No complication was associated with irradiation, and no new neurological deficits occurred. At 1-year follow-up examination, three irradiation-treated patients were pain free and two experienced improvement. In the control group, three patients experienced improved pain relief and two were unchanged. There was a trend toward better outcome at 1 year in the radiotherapy-treated group (p = 0.056). CONCLUSIONS: Preoperative low-dose external-beam irradiation improved clinical outcomes after reexploration and decompression of nerve roots affected by postlaminectomy peridural fibrosis causing radicular pain. The addition of preoperative irradiation may improve outcome in patients who undergo reoperation for recurrent radicular pain associated with a significant amount of peridural fibrosis, particularly now that no antiadhesion product is available for clinical use.

Cervical and cervicomedullary spinal cord stimulation for chronic pain: efficacy and outcomes.

BACKGROUND: The role for spinal cord stimulation (SCS) in the management of chronic spinal cord forms of pain involving cervical dermatomes or the cervicomedullary junction (CMJ) for facial pain remains largely uncharted. OBJECTIVE: To review outcomes with cervical and CMJ SCS performed by a single surgeon, with particular emphasis on complications and efficacy. METHODS: All patients that underwent cervical or CMJ SCS by the lead author were identified and follow-up obtained by telephone questionnaires. Patient demographics, surgical details, outcomes and complications for all patients identified were critically reviewed. RESULTS: Of 121 patients identified that underwent at least trial SCS, 100 underwent permanent lead implantation. Indications for cervical SCS included brachial plexus lesions (8), complex regional pain syndrome (33), degenerative disc disease (4), failed neck surgery syndrome (23), chronic radiculopathy (6) and post-herpetic neuralgia (PHN) (1); for CMJ SCS, indications included trigeminal deafferetiation pain (10), trigeminal neuropathic pain (4), PHN (4) and occipital neuralgia (7). Pain relief was greater along the extremities than axially, and less in the occipital area than in the head or face. Mean pain reduction averaged 56.6% at a mean follow-up of 4.2 years. Of 24 revision surgeries required, 8 were for presumed lead migration or fracture. Complications included 4 CSF leaks, 5 wound infections, and 4 cases of persistent numbness or pain. Pain relief lasted an average of 3.6 years. CONCLUSION: Cervical and CMJ SCS are safe and efficacious and may provide greater relief along the upper extremities than axially, and in the head rather than in the occipital region.

Management of symptomatic intrathecal catheter-associated inflammatory masses.

OBJECTIVE: Intrathecal catheter-associated inflammatory masses (CIMs) are a serious complication of implanted drug pumps. The goal of this study was to review our experience with CIMs, including the pathology of all resected CIMs, and identify objective data which may guide management. METHODS: We performed a retrospective review of 13 patients who developed symptomatic CIMs during continuous intrathecal opioid therapy for chronic pain. Eight patients presented with pain plus neurologic deficit and 5 patients presented with pain alone. RESULTS: CIM resection via laminectomy and intradural exploration was ultimately performed in 8 patients, 3 of whom were initially treated with a non-resective surgical approach (catheter repositioning or pump removal) that failed. All 3 patients who experienced a failure with non-resective surgery had CIMs located in the thoracic spine with a maximum diameter≥13 mm and 2 of these patients had neurologic deficits on presentation. CONCLUSIONS: Our experience, with the largest reported single-surgeon series of patients harboring CIMs, favors early resection, especially in patients with neurologic deficit. Resection may also be a prudent first-line strategy for patients with larger thoracic masses (≥13 mm) regardless of neurologic status. Neurologic deficits engendered by CIM usually improve after resection and the majority of patients in our series would have still elected to have an intrathecal pump for pain control knowing a CIM would have developed.

Perioperative surgical complications of transforaminal lumbar interbody fusion: a single-center experience.

OBJECT: Since its original description in 1982, transforaminal lumbar interbody fusion (TLIF) has grown in popularity as a means for achieving circumferential fusion. The authors sought to define the perioperative complication rates of the TLIF procedure at a large academic medical center. METHODS: For all eligible patients from a consecutive series of 531 TLIF procedures, the institution's complication database and the medical record were reviewed to identify complications. Medical, nonprocedure-related complications such as myocardial infarction and pulmonary embolism were excluded due to inconsistency in the recording of these complications in the database. Rates were calculated for each type of complication, and subgroup analysis was performed to investigate the effect of previous lumbar surgery, and of multilevel versus single-level interbody fusion on complication rates. Odds ratios were calculated and evaluated using chi-square analysis. RESULTS: Five hundred thirty-one patients underwent a TLIF procedure during the study period. Two hundred forty-four patients (46%) had undergone a previous lumbar operation. Interbody fusion was performed at 1 level in 317 patients, at 2 levels in 188 patients, at 3 levels in 24 patients, and at 4 levels in 2 patients. One hundred thirty-five patients (25.4%) had at least one procedure-related complication. The most common complications were durotomy (14.3% of patients) and infection (3.8% of patients). Symptomatic screw misplacement (2.1% of patients) and interbody cage migration (1.8% of patients) were less common complications. The overall complication rate was greater in those patients who had undergone a previous operation (OR 1.75, 95% CI 1.18-2.59; p < 0.01) and in those who had multilevel surgery (OR 1.54, 95 % CI 1.04-2.28; p = 0.03), and the incidence of durotomy was higher in patients who had a previous operation (OR 1.75, 95% CI 1.07-2.87; p = 0.03). These differences were statistically significant. Durotomy also occurred more frequently in patients who had multilevel interbody fusion (OR 1.49, 95% CI 0.92-2.43; p = 0.13). A trend toward higher infection rates in those patients who underwent multilevel interbody fusion was observed (OR 1.5, 95% CI 0.62-3.68; p = 0.49), but this was not statistically significant. Infection rates did not differ between revision and first-time surgeries. CONCLUSIONS: Transforaminal lumbar interbody fusion has gained widespread popularity as a procedure for achieving arthrodesis in the lumbar spine. Complications occurred more often in patients undergoing revision surgery or multilevel interbody fusion. Durotomy and infection were the most common complications in this series.

Follow-up 26 years after dorsal root entry zone thermocoagulation for brachial plexus avulsion and phantom limb pain.

Brachial plexus avulsion and limb amputation are often associated with intractable chronic pain. Dorsal root entry zone (DREZ) thermocoagulation is an effective surgical treatment for upper-extremity deafferentation pain. The authors describe the clinical follow-up and imaging in a patient who underwent DREZ thermocoagulation 26 years ago for postamputation phantom limb syndrome with associated brachial plexus avulsion. This patient continues to have successful pain control without phantom limb sensation and has never experienced a recurrence of his left upper-extremity pain syndrome. This report lends credibility to the notion that, among ablative neurosurgical pain operations, DREZ thermocoagulation may provide the greatest durability of pain control.

Localization of cervical and cervicomedullary stimulation leads for pain treatment using median nerve somatosensory evoked potential collision testing.

OBJECT: Spinal cord stimulation (SCS) is being currently used to treat medically refractory pain syndromes involving the face, trunk, and extremities. Unlike thoracic SCS surgery, during which patients can be awakened from conscious sedation to confirm good lead placement, safe placement of paddle leads in the cervical spine has required general anesthesia. Using intraoperative neurophysiological monitoring, which is routinely performed during these cases at the authors' institution, the authors developed an electrophysiological technique to intraoperatively lateralize lead placement in the cervical epidural space. METHODS: Data from 44 patients undergoing median and tibial nerve somatosensory evoked potential (SSEP) monitoring during cervical laminectomy or hemilaminectomy for placement or replacement of dorsal column stimulators were retrospectively reviewed. Paddle leads were positioned laterally or just off midline and parallel to the axis of the cervical spinal cord to effectively treat what was most commonly a predominant unilateral pain syndrome. During SSEP recording, the spinal cord stimulator was activated at 1.0 V and increased in increments of 1.0 V to a maximum of 6.0 V. A unilateral reduction or abolishment of SSEP amplitude was regarded as an indicator of lateralized placement of the stimulator. A bilateral diminutive effect on SSEPs was interpreted as a midline or near midline lead placement. RESULTS: Epidural stimulation abolished or significantly reduced SSEP amplitudes in all patients undergoing placement for a unilateral pain syndrome. In 15 patients, electrodes were repositioned intraoperatively to achieve the most robust SSEP amplitude reduction or abolishment using the lowest epidural stimulation intensity. In all cases in which a significant unilateral reduction in SSEP was observed, the patient reported postoperative sensory alterations in target locations predicted by intraoperative SSEP changes. Placement of cervical spinal cord stimulators for bilateral pain syndromes often resulted in bilateral but asymmetrical SSEP changes. In no cases were significant SSEP changes, other than those induced using the device to directly stimulate the dorsal surface of the spinal cord, observed. No case of new postoperative neurological deficit was observed. CONCLUSIONS: Somatosensory evoked potentials can be used safely and successfully for predicting the lateralization of cervical spinal cord stimulator placement. Moreover, they can also intraoperatively alert the surgical team to inadvertent displacement of a lead during anchoring. Further studies are needed to determine whether apart from assisting with proper lateralization, SSEP collision testing may help to optimize electrode positioning and improve pain control outcomes.

Single- and multi-unit activity recorded from the surface of the dorsal root ganglia with non-penetrating electrode arrays.

Non-penetrating surface electrode recording techniques are typically associated with field potential recordings, while extracellular recordings from single neurons are made using penetrating metal wire or microfabricated microelectrode arrays. Here, we report on single- and multi-unit neuronal recordings made using non-penetrating electrodes placed on the epineural surface of the dorsal root ganglia (DRG). Across four experiments in anesthetized cats, approximately 40% of the electrodes recorded single- and multi-unit spiking activity with spike-rates that covaried significantly with hindlimb movement. In two intraoperative experiments in humans, compound activity was recorded from the DRG surface in response to peripheral stimulation of the common peroneal nerve. This approach may have advantages over penetrating electrode arrays in terms of clinical acceptability and recording longevity.