Minimally invasive spine surgery in spinal infections.

Infections of the spine have been a constant throughout history. At present there are infections in the spine fostered in part by the same advances in medicine: there are a lot of immunocompromised patients, the life expectancy of patients with chronic diseases is augmented and the increasing number of complex spinal surgeries can result in secondary infection. In this review the main types of infection of the spine and its treatment highlighting techniques in minimally invasive surgery are discussed. Spontaneous pyogenic and nonpyogenic spine infections as well as iatrogenic infections can be treated in a different manner depending on its extension, location and microorganism involved. We will review the use and the indication of percutaneous image-guided techniques, endoscopic and microsurgical techniques with or without use of tubular retractors. We conclude that techniques in minimally invasive surgery in spine infections are safe, effective and have benefits in morbidity of the approach and subsequent patient recovery.

High-dose BCNU and autologous progenitor cell transplantation given with intra-arterial cisplatinum and simultaneous radiotherapy in the treatment of high-grade gliomas: benefit for selected patients.

A phase II study of postoperative high-dose carmustine (HDBCNU), intracarotid cisplatin (CDDP), and radical radiotherapy in patients with high-grade glioma was performed. Patients underwent 4-6 consecutive days of blood hematopoietic progenitor cell (HPC) apheresis without prior mobilization. Chemotherapy included intracarotid CDDP, 60 mg/m2, and BCNU, 900 mg/m2. HPC were infused 48 h after HDBCNU. Whole brain irradiation, up to 50 Gy, was started on the 8th day after HPC infusion. With a median follow-up time of 44 months, median overall survival was 15.5 months. Eight patients (23.5%) are alive free of disease 2-6 years after treatment (seven out of 25 patients with glioblastoma multiforme and one out of nine patients with anaplastic astrocytoma). Survival was influenced by young age, good performance and complete surgical resection. Two patients (5.8%) died of therapy-related complications. Acute hematological toxicity of HDBCNU was moderate, with a full recovery on day 26. No acute pulmonary or hepatic toxicity was found. Late severe neurological toxicity was observed in one third of patients surviving beyond 2 years. We conclude that HDBCNU, 900 mg/m2, intracarotid CDDP and radical radiotherapy appear to benefit some patients with high-grade gliomas, and phase III studies should preferentially select young patients with resectable tumors.

Uniportal endoscopic superior thoracic sympathectomy.

OBJECTIVE: A retrospective study presenting our experience with upper thoracic endoscopic sympathectomy in patients with primary palmar hyperhidrosis. METHODS: One hundred patients (46 women and 54 men) underwent bilateral uniportal endoscopic thoracic sympathectomy since January 1, 1995. Age distribution ranged from 12 to 54 years (mean, 23.4 yr). RESULTS: Sympathectomy on both sides was accomplished within 30 minutes in a single stage. Ninety-six patients (96%) had an uneventful postoperative course and were discharged the following day. Four patients with residual hemothorax required intercostal drainage and were discharged on the third postoperative day. Ninety-six patients were completely satisfied with immediate and permanent relief of palmar perspiration. Compensatory hyperhidrosis was the major complication, which was usually mild and tolerable after reassurance. In only eight patients (8%) was the compensatory hyperhidrosis considered bothersome, requiring treatment with aluminum chloride in ethanol solution at 25%. There was no mortality. Recurrence of palmar hyperhidrosis has been noticed in five patients (5%) during the follow-up period (range, 2-56 mo; mean, 12 mo). At the time of reoperation, a remaining branch of the sympathetic chain could be observed and coagulated. CONCLUSION: We consider thoracoscopic sympathectomy to be a simple, safe, and effective method for treating palmar hyperhidrosis. It is an effective method for treating patients with palmar hyperhidrosis, with a shorter operation time, fewer hospital days, and a better cosmetic result, as compared with the open approaches.

Experimental study following inactive implantation of an auditory brain stem implant in nonhuman primates.

We report changes in the cochlear nuclei (CNs) after 3 months of bilateral auditory deafferentation and simultaneous unilateral implantation of a dummy auditory brain stem implant (ABI) in 6 nonhuman primates (Macaca fascicularis). These specimens were compared to CNs of 9 controls and 7 bilaterally deafferented animals without implantation. The ABI array consists of 3 platinum electrodes mounted on a silicone pad with the back side covered with Dacron. No migration of the ABI was observed. All deafferented animals showed astrocytic reorganization in the CNs. Histologic changes consisted of superficial reactions around the implant, with formation of fibrillar bundles of fusiform cells, and the presence of giant cells close to the Dacron. Other findings were related to surgical trauma. The dummy ABI did not itself provoke serious adverse reactions in the CNs. Our observations support the possibility of ABI reimplantation surgery.

[Neural tube dysfunction and cutaneous lesions]. / Defectos del tubo neural y lesiones cutáneas.

The aim of our article is to underline the cutaneous lesions accompanying spinal disraphysm. We would like to stress the responsibility of physicians, particularly dermatologists, pediatricians, orthopedic surgeons, urologists, neurologists and neurosurgeons to recognize as early as possible these cutaneous stigmata. In this way patients will be studied and treated as soon as possible. No cutaneous lesion in the posterior middle line of the back or close to it should be removed until any possibly associated malformation has been thoroughly studied. Otherwise the diagnosis of a subyacent spinal disraphysm might be unduly delayed and thus allow the appearance of irreversible neurological deficits. Cutaneous lesions associated with spinal disraphysm are: areas of atrophic skin, aplasia cutis congenita, congenital skin scars, dermal pits, dermal sinuses, dyschromic lesions, hyperpigmented lesions, abnormal pilifications, vascular lesions, subcutaneous lipomas, polipoid lesions simulating tails, neurofibromas, melanocitic nevus and some lesions of tumoral origin. Of there the most common cutaneous lesion associated with spinal disraphysm is the lipoma, followed by the dermal sinuses, the anomalus pilifications and the angiomas.

[Auditory brain stem potentials evoked by electrical stimulation of cochlear nuclei during central auditive implant setting]. / Potenciales auditivos troncoencefálicos evocados por la estimulación eléctrica de los núcleos cocleares durante la colocación de implantes auditivos centrales.

INTRODUCTION: The implantation of a stimulator over the surface of the cochlear nuclei can provide a partial auditive capability to patients deaf due to a bilateral lesion of the 8th nerve. Intraoperative monitoring of short latency electrically-evoked potentials is useful to asses the correct positioning of the implant, specially when there are anatomical distortions. PATIENTS AND METHODS: Evoked potentials from two patients with type II neurofibromatosis were recorded during implantation surgery, using a blanker system to eliminate the stimulus artifact. RESULTS: In both cases, two-peak vertex-positive responses were obtained, with latencies between 0.4-0.5 and 1.2-1.4, respectively. This responses are similar to the most frequent response described. DISCUSSION: Intraoperative monitoring of electrically-evoked auditory brainstem responses is a useful technique to confirm the correct positioning of the cochlear stimulator. The study of the morphology of these responses can help to understand the mechanisms involved in the generation by the brainstem of the auditive evoked potentials. More experience on this subject is needed to establish a correlation between intraoperative results and postoperative stimulator function.

Auditory brainstem implantation in primates: lessons for human surgery and application.

We report on the surgical technique for surface electro-auditory prosthesis (EAP) implantation, pathological changes occurring at the cochlear nucleus complex (CNC), and its relation with electrical stimulation. Fourteen Macaca fascicularis were operated upon for a translabyrinthine bilateral auditory neurectomy, and simultaneous unilateral EAP implantation. Six animals were not stimulated, and the remaining eight were connected to an external active device. Stimulation was planned for 1000 hours. Biotolerance to the materials was adequate without significant reactions in the CNC surface, but an ependymal reaction. Lesions attributed to surgical trauma were also found. Two animals being stimulated could not complete the planned course due to cable break or EAP extrusion. One stimulated animal developed an asymptomatic brainstem abscess. A good knowledge of CNC topography is required to avoid surgical trauma. Externally connected devices may facilitate extrusion of the EAP or ascending infections.

Duraplasty with freeze-dried cadaveric dura versus occipital pericranium for Chiari type I malformation: comparative study.

During the period from October 1, 1989 to October 1, 1995 a total of 26 cases of Chiari type I malformation not associated with syringomyelia were attended in our Hospital. All patients underwent cranio-cervical decompression, with occipital craniectomy and removal of the posterior arch of C1. In 3/26 (11.5%) cases an additional C2 laminectomy had to be performed and in 1/26 (3.8%) case the C3 laminae were also removed. A first group of 13 patients underwent dural repair with freeze-dried cadaveric dura sutured with continuous 4-0 Vicryl running stitches, reinforced with fibrin sealant (Tissucol). A second group of 13 patients underwent duraplasty with autogenous occipital pericranium also sutured with continuous 4-0 Vycril but no fibrin sealant at all was added. In the first group, in which freeze-dried cadaveric dura plus Tissucol was used, there were 2/13 (15.3%) cases of CSF leak, requiring some additional skin stitches to stop the leak. In 5/13 (38.4%) cases there were notorious subcutaneous CSF accumulations that required repeated punctures plus compressive bandage. In 6/13 (46.1%) pseudomeningoceles appeared that took a year to clear completely. In the 13 patients who underwent dural repair with autogenous occipital pericranium watertight closure was achieved with sutures only, no fibrin sealant was added at all. Neither CSF leaks through the wound nor subcutaneous CSF accumulations were noted. We conclude that, in our hands, autologous pericranium taken from the occipital area, gives better results than freeze-dried cadaveric dura mater in duraplasty for surgical repair of Chiari type I malformation.

Surgical treatment of anterior skull base tumours.

Skull base tumours represent a special challenge to surgeons due to the complex anatomy of the area. While small tumours are easy to remove, large lesions can pose complex situations. The most difficult aspects are not only the approach and removal, but specially the repair of the defects created by the resection of the tumour. We present here our experience with the surgical removal of tumours on the anterior skull base. To achieve a good approach, we resort to a bifrontal craniotomy including the cilliar arches. To obtain a skull base bone flap that can be used for repair at the end of the procedure, we remove the roof of the nose and a part of the medial wall and roof of both orbits. While the tumour is removed, the skull base bone flap is autoclaved to kill all tumoural cells. At the end of the procedure this bone flap is replaced, wrapped with a flap of pericranium. Provided no orbit needs to be emptied, no other flap is needed to reconstruct the area. One advantage is that the surgical cavity is not occluded with tissues, thus facilitating early identification of any recurrence. The area can be explored with the aid of an endoscope introduced into the nasal cavities through the nostrils, and in case of doubt, biopsies taken from all suspicious area. Our technique facilitates the repair of the surgical defect, and while not compromising the healing process it has a very low incidence of CSF leaks and infections.

Repair of dural defects in awkward areas-technical note.

Dural tears located at the base of the skull are difficult to repair due to the difficulties in the appropriate access and the fragility of the dura in such areas. In our experience the biggest problem when attempting to perform a dural repair in a deep narrow field is not to place the stitches, but rather to set the knots. A newly designed, easy-to-learn technique has been developed for dural closure in these situations. We present here a new technique for dural suturing of special interest when the space available is limited. In our hands it is possible to obtain a watertight dural closure in most microsurgical operations performed through a small hole and/or into a narrow, deep surgical field. These techniques can also be applied during a secondary procedure following development of a postoperative CSF leak. While simple and easy to learn, these techniques require practice in the laboratory setting before clinical application.

Dorsal root repair by means of an autologous nerve graft: experimental study in the rat.

Rat dorsal root regeneration was studied after 6th and 7th cervical root surgical removal and replacement with an autologous graft of peripheral nerve harvested from the surval nerve from dorsal root ganglion to dorsal horn. Histological studies showed axonal regeneration within the grafts. When the distal end of the graft was placed inside the posterior horn of the spinal cord by use of a myelotomy, axonal sprouts (revealed by the transganglionic staining method of horseradish peroxidase or HSP) reached the neurones of the posterior horn in a limited fashion.

Surgical technique for cranio-cervical decompression in syringomyelia associated with Chiari type I malformation.

Our purpose is to present our results with the surgical treatment of syringomyelia associated with Chiari type I malformation. Between October 1989 and October 1995, twenty-eight patients underwent a sub-occipital craniotomy and a C1 laminectomy. After dura mater opening the cerebellar tonsils were mobilised. Neither catheter, nor plugging of the obex, nor tonsillar tissue removal was performed. The dura mater was enlarged by means of a wide graft to create a new cisterna magna of adequate size. Postoperative MRI scans showed an ascent of the cerebellum of 4.3 +/- 4.8 mm (measured by the fastigium to basal line), as well as of the brainstem (mean migration of the mesencephalon-pons junction of 4.3 +/- 3.3 mm). The tonsils emigrated cranially 6.5 +/- 4.8 mm. While preoperative mean syringo-cord ratio was 66.3% +/- 13.3, post-operatively was 12.1% +/- 12.7 (p < 0.0001). A complete collapse of the syrinx was observed in 39% of the patients. Long-term improvements were obtained in 73% of the cases and 27% were unchanged. No patient got worse. We conclude that in the treatment of syringomyelia associated with Chiari I malformation an artificial cisterna magna of sufficient size must be created. This is achieved by means of an extensive sub-occipital craniotomy and C1 laminectomy, followed by dural opening. Small bone removal with limited enlargement of the posterior fossa often results in failures of treatment and recurrences. Tonsillar removal is not necessary to obtain a good reconstruction of the cisterna magna.

Shunt malfunction in relation to shunt infection.

Ventriculo-peritoneal shunt malfunction may be caused by shunt infection which may not be clinically apparent as the cause of the malfunction by standard diagnostic criteria. This suggests that the real incidence of infected shunts might be higher than previously suspected. In order to study the relationship between infection and shunt malfunction, we followed a protocol over five years (54 V-P shunts) consisting of (1) removal of the malfunctioning shunt and replacement in the same surgical procedure with a new one or institution of an external ventricular drainage for 8 days (if there were clear signs of infection), (2) culturing of CSF and every part of the removed shunt, and (3) intravenous antibiotic treatment (Vancomycin 1g./12h + Ceftriaxone 1g./12h) for five days after the new V-P shunt had been inserted. In those cases in which an external ventricular drainage had been placed, its tip and a portion of the new V-P shunt were also cultured. The results showed that although CSF cultures were negative in 49/54 cases (90.7%), cultures of the removed shunts were positive in 32/54 (59.2%), most of them (21/32, 65.6%) for Staphylococcus coagulase negative organisms. The CSF samples obtained by puncturing the reservoir on admission to Hospital were positive only in 5 out of 54 cases (9.2%), only in those showing clinical features of infection. In the remaining cases, 27 out of 54 (50%) the CSF cultures were negative but the shunt cultures proved positive and required further treatment. For the newly inserted shunts (173) CSF was collected through the shunt during the surgical procedure, and a small piece of the extra-tube from the ventricular and from the peritoneal catheter were obtained and cultured. All the six shunts (6/173, 3.4%) that showed positive cultures after insertion had to be replaced within a period of three to four weeks due to malfunction (range 26 +/- 7 days), indicating that the systematic culture of CSF and tubing helps to predict which shunts will soon need to be replaced due to infection. We conclude that CSF culture alone does not rule out infection in cases of shunt malfunction. The percutaneous CSF obtained from the shunt reservoir admission is particularly prone to show negative cultures even when the shunt is colonized by bacteria.

Chiari type I malformation, glossopharyngeal neuralgia and central sleep apnoea in a child.

We describe the case of an 8-year-old child who presented with sleep breathing disorders associated with glossopharyngeal neuralgia. Polysomnographic studies showed central sleep apnoea lasting 10 to 18 seconds in an average frequency of 63 times for every hour of sleep. Magnetic resonance imaging (MRI) studies showed a caudal displacement of the cerebellar tonsils down to C3 level, associated with a syringomyelic cavity in the upper cervical cord and an extramedullary cystic collection at C2. Surgical decompression of the cranio-cervical junction completely relieved the apnoea and the glossopharyngeal neuralgia immediately following the procedure. MRI study performed one month later showed the complete disappearance of the syringomyelic cavity. Two years later this child remains asymptomatic. In childhood the association of Chiari type I malformation with sleep apnoea and glossopharyngeal neuralgia has not been previously reported. The successful outcome after surgery suggests a compressive mechanism on the brainstem and on the IX cranial nerve to explain these two clinical features in our patient.

Surgical treatment of insular gliomas.

Surgical treatment of glial tumours arising in the insula is specially challenging due to the proximity of the internal capsule. Although small insular gliomas have been removed safely by a transylvian approach, in large dominant insular tumours only biopsy has been recommended to avoid postoperative deficits. Unfortunately that is a suboptimal form of treatment as low grade supratentorial gliomas should be removed radically to prevent tumour progression, malignization and to increase the recurrence-free-interval. Addition of radiotherapy to partial removal is associated with a much higher incidence of recurrences and early malignizations compared to radical removal and no radiotherapy. Between 1st October 1989 and 1st September 1996 we treated twenty-three patients harbouring insular gliomas. To increase the radicality of the resection the surgical procedure was performed under local anaesthesia whenever possible, as general anaesthesia usually leads to more conservative resections. In 20/23 (86.9%) patients complete resection was accomplished, and subtotal in three (13.1%). The removed tumours were: two oligodendrogliomas, five grade I astrocytomas, nine grade II, four grade III and three grade IV. Postoperative neurological deficits occurred in five patients. Four suffered a hemiparesis (that recovered in an average of 6 months) and one a motor dysphasia which took a week to recover. Two of the seventeen patients operated on for low grade insular gliomas underwent malignant change. We conclude that complete surgical removal of insular gliomas should be considered and at least attempted in all cases.

Occult spinal dysraphism: a neurosurgical problem with a dermatologic hallmark.

Lumbosacral congenital cutaneous lesions have been recognized for a long time by neurologists and neurosurgeons as markers of occult spinal defects, but only a few cases have been published and discussed in the dermatologic literature. Based on a case report, we emphasize the importance of early diagnosis of these lesions, the use of new diagnostic techniques, and the correct management.

Response of experimental epileptic focus to focal ionizing radiation.

An experimental model of cobalt-induced epilepsy was performed on 15 cats. 3 months later, they were irradiated by means of a gamma source with a total target dose of 10 Gy. One month after irradiation all EEG recordings returned to normal, while a control group maintained the epileptiform traces. Histological study of the irradiated foci showed neuronal reafferentation. The action mechanism of ionizing radiation over epileptogenic foci in relation to this reafferentation and neuronal plasticity mechanisms is discussed.

Use of frozen cranial vault bone allografts in the repair of extensive cranial bone defects.

In cranioplasty complexity is proportional to the size of the detect, particularly if greater than 50 cm2. If the patient's own bone flap is not available, allogenic frozen bone graft can be used instead. Between June 1990 and June 1995 twenty cranioplasties with allogenic frozen bone grafts were performed. Age of patients ranged between 23 and 63 years (average 38.4 years). Male/female ratio was 2:1.7. Size of craniectomy ranged between 65 and 150 cm2 (average 83.3 cm2). Follow-up ranged between 10 and 58 months (average 41 months). Donors were tested to rule out transmissible diseases, infections, sepsis and/or cancer. Bone grafts were removed under aseptic conditions, microbiological cultures were taken, wrapped in a gauze soaked with Gentamicin sulphate and Bacitracin, sealed in three sterilised vinyl plastic bags, and stored in a deep freezer for a minimum of 30 days (range 36-93 days, average 67 days), at a temperature of -80 degrees C. Grafts were placed in the defect after a step was carved on its borders to facilitate the contact between host and graft. Vancomycin 1 g. IV/12 hours and Ceftriaxone 1 g. IV/12 hours were administered for five days. Grafts were covered by means of scalp flaps. Only one required a musculocutaneous free flap. None was exposed, extruded or had to be removed. Plain skull X-ray studies showed progressive remodelling of the grafts. Partial resorption was observed in two (2/20, 10%) and loss of thickness in another 3/20 (15%), but with no changes in the contour. Biopsies were taken in 3/20 (15%) cases at a second surgical procedure. Areas of osteoclastic resorptive activity mixed with others of osteoblastic bone apposition, showed replacement with new bone. We conclude that cranial vault frozen allografts are a good alternative to autologous bone when the latter is absent or not present in sufficient amount.

Operative monitoring of hand and axillary temperature during endoscopic superior thoracic sympathectomy for the treatment of palmar hyperhidrosis.

OBJECTIVE: To find out how much the temperature in the palm rises after upper thoracic sympathectomy for palmar hyperhidrosis, and correlate the temperature with the outcome. DESIGN: Retrospective study. SETTING: University hospital, Spain. SUBJECTS: 73 patients (34 women and 39 men, age range 16-42 years, mean 26) who were operated for palmar hyperhidrosis between 1 January 1995 and 31 December 1997. INTERVENTIONS: Bilateral thoracic endoscopic sympathectomy during which the temperature was monitored on the skin of both axillae and thenar eminences, and in the oesophagus. MAIN OUTCOME MEASURES: Morbidity, alleviation of hyperhidrosis, recurrence rate, and differences in temperature postoperatively. RESULTS: There was minor bleeding during operation in 25 cases (34%), but in only 4 was it sufficient to require insertion of a drain; 2 patients developed transient Homer's syndrome; but the most common complication was compensatory hyperhidrosis (n = 52, 71%). In only 5 was this other than mild and required treatment with aluminium chloride in ethanol 25%. Palmar hyperhidrosis was alleviated in all cases, axillary sweating was considerably improved, and there was improvement in the feet in 56 (77%). There were 5 recurrences, all on the right side, during a mean follow up of 9 months (range 2-36), but in no case was the sweating severe. In almost all cases the temperature of the palm was less than that of the axilla before operation by a mean (SD) of 0.9 (0.3) degrees C. The rise in temperature varied from 1.7 (0.4) degrees C to 2.6 (0.4) degrees C. In the 5 patients who developed recurrences the increase was less (0.5 (0.4) degrees C). CONCLUSION: Thoracic endoscopic sympathectomy is safe, simple, and effective in treating palmar hyperhidrosis that has not responded to conservative treatment. Intradermal monitoring is an accurate and cost-effective way of monitoring temperature during operation. Although it is essential to achieve a rise in temperature of 1 degrees C, our most important finding was that the final temperature in both hands and axillae should be above 35 degrees C and as near as possible to 36 degrees C.

Cranioplasty with autogenous autoclaved calvarial bone flap in the cases of tumoural invasion.

When a bone flap is raised in the course of a craniotomy, the ideal is to replace it at the end of the procedure. When it is invaded by tumoural cells, it cannot be replaced due to the risk of tumoural recurrence. In these cases we have autoclaved the bone flap to be able to replace it with no fear of tumoural recurrence. Between October 1989 and October 1995 sixty-two patients required autoclaving of the bone flap in the course of a craniotomy due to tumoural invasion (thirty-five meningiomas, sixteen bone tumours, five metastases, and eight scalp tumours). The infiltrated bone flaps were removed, cleaned, autoclaved for 20 minutes at 134 degrees C and 1 kg/cm2 and re-implanted. Patients were followed-up for 10 to 58 months (average 41 months). At every follow-up visit skull x-ray studies, clinical examination, and photographs were done. When needed a CT scan was performed to assess the thickness of the bone flap. On follow-up roentgenograms partial resorption was observed in twelve cases (19.3%). CT scan studies showed loss of thickness in another thirty-five cases (56.4%). Meanwhile the external aspect remained unchanged. In six cases (3.2%) biopsies of the bone flaps were taken at a second surgical procedure. They showed newly formed bone partly re-populated by osteocytes but retaining areas of sequestered bone. We conclude that autoclaved bone, if replaced with direct contact with living bone, it is gradually repopulated with osteocytes. Cranial vault autoclaved autologous bone flap is a good alternative when the original bone flap is invaded but not destroyed by tumoural cells.