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PubMed1990

Bubble-induced dysfunction in acute spinal cord decompression sickness.

Five anesthetized dogs undertook a chamber dive, on air, to 300 feet of seawater for 15 min. After the dive, spinal cord decompression sickness was detected by recording a reduced amplitude of the somatosensory evoked potential compared with predive base-line values. After the diagnosis of decompression sickness and rapid perfusion fixation of the animal, the spinal cord was removed and examined histologically. Numerous space-occupying lesions (SOL) that disrupted the tissue architecture were found in each cord, mainly in the white matter. The size and distribution of the SOL were determined using computerized morphometry. Although SOL occupied less than 0.5% of the white matter volume, we tested a number of algorithms to assess whether the SOL may have been directly involved in the loss of spinal cord function that followed the dive. We determined that the loss of somatosensory evoked potential amplitude may be attributed to the SOL if 30-100% of the spinal cord fibers that they displaced were rendered nonconducting. A number of possible mechanisms by which SOL may interfere with spinal nerve conduction are discussed.

Animals↗

PubMed2002

Using animal data to improve prediction of human decompression risk following air-saturation dives.

To plan for any future rescue of personnel in a disabled and pressurized submarine, the US Navy needs a method for predicting risk of decompression sickness under possible scenarios for crew recovery. Such scenarios include direct ascent from compressed air exposures with risks too high for ethical human experiments. Animal data, however, with their extensive range of exposure pressures and incidence of decompression sickness, could improve prediction of high-risk human exposures. Hill equation dose-response models were fit, by using maximum likelihood, to 898 air-saturation, direct-ascent dives from humans, pigs, and rats, both individually and combined. Combining the species allowed estimation of one, more precise Hill equation exponent (steepness parameter), thus increasing the precision associated with human risk predictions. These predictions agreed more closely with the observed data at 2 ATA, compared with a current, more general, US Navy model, although the confidence limits of both models overlapped those of the data. However, the greatest benefit of adding animal data was observed after removal of the highest risk human exposures, requiring the models to extrapolate.

Algorithms↗

PubMed2006

Short oxygen prebreathing and intravenous perfluorocarbon emulsion reduces morbidity and mortality in a swine saturation model of decompression sickness.

Disabled submarine (DISSUB) survivors will achieve inert gas tissue saturation within 24 h. Direct ascent to the surface when saturated carries a high risk of decompression sickness (DCS) and death, yet may be necessary during rescue or escape. O(2) has demonstrated benefits in decreasing morbidity and mortality resulting from DCS by enhancing inert gas elimination. Perfluorocarbons (PFCs) also mitigate the effects of DCS by decreasing bubble formation and increasing O(2) delivery. Our hypothesis is that combining O(2) prebreathing (OPB) and PFC administration will reduce the incidence of DCS and death following saturation in an established 20-kg swine model. Yorkshire swine (20 +/- 6.5 kg) were compressed to 5 atmospheres (ATA) in a dry chamber for 22 h before randomization into one of four groups: 1) air and saline, 2) OPB and saline, 3) OPB with PFC given at depth, 4) OPB with PFC given after surfacing. OPB animals received >90% O(2) for 9 min at depth. All animals were returned to the surface (1 ATA) without decompression stops. The incidence of severe DCS < 2 h after surfacing was 96%, 63%, 82%, and 29% for groups 1, 2, 3, and 4, respectively. The incidence of death was 88%, 41%, 54%, and 5% for groups 1, 2, 3, and 4, respectively. OPB combined with PFC administration after surfacing provided the greatest reduction in DCS morbidity and mortality in a saturation swine model. O(2)-related seizure activity before reaching surface did not negatively affect outcome, but further safety studies are warranted.

Animals↗

PubMed2002

Acute hydrocephalus following a Chiari I decompression.

Complications of posterior cranial fossa decompression for Chiari malformations are uncommon. We present three patients who developed infratentorial supracerebellar hygromas causing acute hydrocephalus after posterior cranial fossa decompression.

Acute Disease↗

PubMed2001

Microvascular decompression for hemifacial spasm: a long-term follow-up of 1,169 consecutive cases.

We analyzed the records of 1,169 patients with hemifacial spasm (HFS) who underwent microvascular decompression (MVD) and were followed up for more than 6 months from January 1987. The mean follow-up duration was 23.8 months (6-145 months). Excellent surgical outcome was obtained in 90.5% and good in 4.5%, giving an overall success rate of 95.0%. There was statistically significant relationship between vertebral artery (VA) shift and side of symptom. Permanent facial weakness and hearing impairment were 1.4% and 2.3%, respectively. There were no anatomical differences at the root entry zone (REZ) and significant differences of surgical outcome in young HFS (34 patients). Factors such as type of offender, severity of compression on the facial nerve root, and the degree of decompression of the REZ on postoperative MRI did not correlate with surgical outcome.

Adult↗

PubMed2003

Reformation of the posterior atlanto-occipital membrane following posterior fossa decompression with subsequent constriction at the craniocervical junction.

The posterior atlanto-occipital membrane (PAO) contributes little to craniocervical stability and is generally underappreciated and incised with most suboccipital craniectomies. We report a case of a child who underwent posterior fossa decompression for Chiari I malformation with syringomyelia whose symptoms had not resolved months after surgery. A secondary exploratory operation revealed a healed constricting PAO which had been incised linearly at the initial operation. This patient's symptoms improved soon after the second surgery. We propose that attention be given to this membrane, and if it is incised with underlying dura mater as in a standard posterior fossa decompression, it should be removed or cauterized separately and laterally to inhibit its reformation.

Arnold-Chiari Malformation↗

PubMed2003

Microvascular decompression for trigeminal neuralgia in patients with multiple sclerosis.

AIMS: To assess whether microvascular decompression (MVD) is a safe and efficacious treatment for patients with trigeminal neuralgia (TGN) and multiple sclerosis (MS). METHODS: Case records were reviewed of all patients with TGN and MS who underwent posterior fossa exploration with a view to MVD between 1993 and 2001. In all patients, magnetic resonance tomoangiography (MRTA) demonstrated vascular compression. RESULTS: Nine patients were included in the study. Seven patients underwent MVD alone; in 2 patients a partial sensory rhizotomy of the trigeminal nerve was added to the decompression. All patients had excellent initial pain relief. Recurrence of neuralgia was noted in 5 patients after MVD and in 1 of the 2 patients after partial sensory rhizotomy. Long-term pain relief was obtained in 1 patient who underwent a redo MVD after postoperative MRTA scans demonstrated recurrent vascular compression of the root entry zone (REZ). Thus only 4 out of 9 patients maintained pain relief. In addition, 3 patients experienced transient worsening of their MS. CONCLUSIONS: Although MVD provides good initial pain relief, the recurrence rate is much higher than that obtained in 'idiopathic' TGN. Although all procedures for the treatment of TGN are worse than those for idiopathic TGN, it is concluded that because of the high recurrence rate together with the morbidity associated with the procedure MVD should not be offered to patients with TGN and MS.

Adult↗

PubMed1997

Microvascular decompression for trigeminal neuralgia: no relation between sensory disturbance and outcome.

Trigeminal nerve microvascular decompression (MVD) relieves the pain in a great majority of patients. However, there has been a debate regarding whether the pain-relieving effect is due to the decompression itself or a surgical trauma to the nerve. In 37 consecutive patients, the facial sensibility was quantitatively assessed and the function of other cranial nerves was investigated before and after MVD. The patients were followed for 1-5 years (mean 3.4 years) to assess the surgical outcome. Twelve patients (32%) experienced a mild postoperative sensory deficit assessed by clinical examination. When measured quantitatively with electrical stimulation, sensory thresholds for perception and pain were elevated more than 25% in 16 of the patients (43%). All together 19 patients (51%) did not have any sensory deficit as assessed by either of the two methods used. No severe postoperative cranial nerve dysfunctions were noted in this series. Three patients (8%) had a recurrence of pain at 7-9 months postoperatively. Two of those patients had a moderate elevation of measured sensory thresholds. All 19 patients with no cranial nerve deficits after MVD experienced an excellent pain relief. It seems that trauma to the trigeminal nerve is not a prerequisite for obtaining pain relief after MVD for trigeminal neuralgia.

Adult↗

PubMed1982

Creatine phosphokinase activities in rainbow trout, Salmo gairdneri, associated with rapid decompression.

Serum creatine phosphokinase (CPK) activity levels were monitored in rainbow trout following rapid decompression. Serum activity was elevated 8.5-fold at 24 h and 15-fold at 48 h after decompression from 100-feet sea water (fsw) dives of 1 1/2 h duration. Serum enzyme activity was unchanged in the 66-fsw group. Stress results indicated a proportional relationship exists between serum CPK activity and muscular activity. CPK activities were found to be 1,023 in skeletal (white) muscle and 255 mumol . min-1 . g-1 in heart ventricle. Elevated CPK activity was not associated with tissue necrosis and is considered a consequence of increased anaerobic respiration stimulated by muscular activity and pressure-induced peripheral hypoxia.

Animals↗

PubMedDate not supplied

Severe orbitopalpebral emphysema after nose blowing requiring emergency decompression.

PURPOSE: Orbital emphysema is a frequent condition associated with medial wall fractures after blunt trauma. It is usually a benign, self-limited phenomenon. The authors are unaware of previous reports of severe orbital emphysema needing emergency decompression with no evidence of any previous significant trauma such as the case presented herein. METHODS/RESULTS: A 51-year-old woman had painful swelling of the left orbital region that prevented her from opening her eyelids. She complained of a coincident cold with abundant mucous rhinorrhea. She had blown her nose vigorously several times. A computed tomography scan revealed a left proptosis, an extensive orbitopalpebral emphysema, and a blowout fracture of the medial wall of the left orbit. A complete ophthalmic examination was only possible after a needle decompression. No significant ocular damage was observed, so outpatient treatment was provided. Twenty-eight hours later, the swelling had almost disappeared, and the ocular assessment was normal. CONCLUSIONS: A forceful expiratory effort raising intranasal pressure may cause a medial wall orbital fracture. If the airway hyperpressure episodes are repeated, a severe orbitopalpebral emphysema may develop. Should there be any suspicion of vascular compression, it must be drained to allow the assessment of visual function and theoretically prevent a potentially irreversible ischemic visual loss.

Decompression, Surgical↗

PubMed2003

Cerebral edema leading to decompressive craniectomy: an assessment of the preceding clinical and neuromonitoring trends.

The aim of this study was to examine the pre-operative clinical and neuromonitoring courses in patients with a decompressive craniectomy to assess and to compare clinical and neuromonitoring signs indicating extensive cerebral edema. We conducted a retrospective analysis of the clinical signs and courses of simultaneous monitoring of intracranial pressure (ICP) and cerebral oxygenation (PtiO2) in 26 consecutive patients who were sedated and treated with a decompressive craniectomy due to extensive cerebral edema after aneurysmal subarachnoid hemorrhage (SAH) (n = 20) or severe head injury (SHI) (n = 6). Pathological monitoring trends always preceded clinical deterioration. In 18 of 26 patients extensive cerebral edema was indicated solely by increasing ICP > 20 mmHg or decreasing PtiO2 < 10 mmHg or both. Anisocoria occurred in only 8 of 26 patients. As opposed to SHI patients, 9 of 20 SAH patients showed decreasing PtiO2 as first warning sign clearly before neurological deterioration or ICP increase. This series shows the utility of combined ICP and PtiO2 monitoring in patients who develop extensive cerebral edema. Pathological monitoring trends indicate deterioration prior to clinical signs which offers a wider therapeutical window. PtiO2 monitoring appears to be particularly valuable after aneurysmal SAH as adjunct to ICP monitoring and CT imaging.

Adolescent↗

PubMed1985

Neurologic presentation of decompression sickness and air embolism in sport divers.

In a retrospective study of scuba divers with neurologic injuries, we found that mild symptoms were common. Seventy divers had decompression sickness, most often with paresthesias or numbness, rarely with paresis. Thirty-nine divers had air embolism that often caused unconsciousness or mild symptoms of cerebral injury. Many divers with neurologic decompression sickness gave histories of dives that were within conventional limits, and many with air embolism gave no history of breath-holding during ascent. Mild symptoms sometimes regressed spontaneously. Recompression delays were responsible for poor responses to therapy.

Adolescent↗

PubMed2004

Delayed resolution of Chiari I-associated hydromyelia after posterior fossa decompression: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: The expected time interval for resolution of hydromyelia after Chiari I decompression is lacking in the literature. This case report highlights one instance of delayed resolution of Chiari-induced hydromyelia. CLINICAL PRESENTATION: We report an adolescent girl with a Chiari I malformation and hydromyelia. INTERVENTION: A suboccipital craniectomy and C1 laminectomy with intradural exploration and duraplasty were performed. Serial imaging at 1 and 2 years after posterior cranial fossa decompression with duraplasty demonstrated no change in the size of the hydromyelia. At 3 years after surgery and before reoperation for continued hydromyelia, repeat magnetic resonance imaging demonstrated significant diminution of the fluid cavity. If this hydromyelia did resolve as a result of surgery, the interval for radiological observation clearly needs to be reconsidered. CONCLUSION: Unfortunately, this is an area in which the literature is lacking. With this case as a nidus, studies are now necessary to determine the range of time necessary for Chiari I malformation-related hydromyelia to resolve.

Adolescent↗

PubMed2004

Ulnar nerve entrapment neuropathy at the elbow: simple decompression.

Ulnar nerve entrapment neuropathy at the elbow, or the cubital tunnel syndrome, is frequently encountered in neurosurgical practice as the second most common peripheral nerve entrapment after carpal tunnel syndrome. Patients typically present with weakness or atrophy of the hand as well as paresthesias in the ulnar nerve distribution. The diagnosis can be confirmed with a careful clinical examination and electrophysiological studies. Patients who have failed conservative therapy are considered for surgery. Although a number of surgical options are available, simple decompression of the ulnar nerve can achieve satisfactory results with appropriate patient selection. We describe the relevant anatomy and surgical techniques for simple in situ decompression of the ulnar nerve at the elbow.

Decompression, Surgical↗

PubMed2005

Simple decompression versus anterior submuscular transposition of the ulnar nerve in severe cubital tunnel syndrome: a prospective randomized study.

OBJECTIVE: The authors report the results of a clinical series of selected patients with severe cubital tunnel syndrome. The degree of ulnar nerve compression was evaluated by use of a grading system that includes measurements of motor and sensitive function. The submuscular transposition with flexor-pronator mass Z lengthening was compared with simple decompression through a prospective randomized study. METHODS: From February 1998 to June 2003, 70 patients with severe cubital tunnel syndrome were included in this study: 35 patients were submitted to simple decompression (Group A), and 35 patients were treated by anterior deep submuscular transposition (Group B). The preoperative status was determined by use of Dellon's classification. The selected patients had Dellon's Grade 3 (severe syndrome). The mean follow-up period after surgery was 47 months for Group A and 46.94 months for Group B. RESULTS: Postoperative clinical and electrophysiological outcomes were assessed 6 months after surgery in all 70 patients. According to the Bishop scoring system, 19 patients (54.3%) of Group A were clinically graded as excellent, 9 (25.7%) were graded as good, and 7 (20%) were graded as fair; in Group B, 18 patients (51.43%) were graded as excellent, 11 (31.43%) as good, and 6 (17.14%) as fair. Neither severe complications nor recurrences were observed in the two groups. CONCLUSION: No statistically significant difference was found between the two groups with regard to the clinical or the electrophysiological outcome. The surgical treatment gains in Group A and B were 80% and 82.86%, respectively (good to excellent results).

Adult↗

PubMed2005

Paradoxical cerebral herniation secondary to lumbar puncture after decompressive craniectomy for a large space-occupying hemispheric stroke: case report.

OBJECTIVE AND IMPORTANCE: The risk of transtentorial herniation after removal of cerebrospinal fluid from the lumbar cistern in the setting of a supratentorial lesion with significant mass effect, increased cerebrospinal fluid pressure, or midline shift is well known. We report a case of cerebral herniation from intracranial hypotension (so-called paradoxical herniation) secondary to a lumbar puncture 1 month after decompressive hemicraniectomy for a large right hemispheric stroke. CLINICAL PRESENTATION: A 50-year-old woman was transferred to our neurosurgical service for obtundation 4 days after a lumbar puncture to rule out meningitis and 1 month after decompressive craniectomy for a large right hemispheric stroke. INTERVENTION: Eighty grams of mannitol was administered before transfer. On arrival at our hospital, the patient was intubated and a computed tomographic scan was performed. The patient was diagnosed with low-pressure herniation after review of the computed tomographic scan. Rehydration was initiated, and the patient was placed in the Trendelenburg position. She became easier to arouse, but her pupils remained dilated. She experienced a sudden severe cardiac arrhythmia leading to a cardiac arrest. Attempted resuscitation was unsuccessful, and the patient was pronounced dead. CONCLUSION: Lumbar punctures may result in lethal intracranial hypotension in patients after hemicraniectomy and are thus contraindicated unless care is taken to remove the pressure gradient of atmospheric air across the lumbar cistern.

Cerebral Angiography↗

PubMed2006

Microsurgical cervical nerve root decompression by anterolateral approach.

OBJECTIVE: Cervical radiculopathy caused by a posterolateral soft disc herniation or spondylosis is a common pathology. METHODS: Decompression of a stressed cervical nerve root is a routine neurosurgical procedure. Most of the time it is achieved through an anterior approach and, less frequently, through a posterior approach in specific indications. RESULTS: According to the principles that an anterolateral compression must directly be reached and that working in the vicinity of the vertebral artery is safe under visual control, we developed the anterolateral approach to the cervical intervertebral foramen and the nerve root using a minimally invasive technique to remove the offending process. CONCLUSION: Microsurgical cervical nerve root decompression by anterolateral approach is a minimally invasive technique, permitting one to remove the offending process staightforwardly. The disc and bone resections are minimal. This method avoids osteoarthrodesis or arthroplasty with disc prosthesis. This technique is efficient with good results and low morbidity.

Cervical Vertebrae↗

PubMed2006

Cystic dilation of the conus ventriculus terminalis presenting as an acute cauda equina syndrome relieved by decompression and cyst drainage: case report.

OBJECTIVE AND IMPORTANCE: The ventriculus terminalis of the conus, or "fifth ventricle" refers to the ependymal-lined space in the middle of the conus that is present in childhood and whose persistence into adulthood is rare. A number of cases of cystic dilatation of the ventriculus terminalis have been described in adulthood. Patients tend to present with either pain alone or gradually progressive conus or cauda equina syndromes with varying degrees of recovery after cyst drainage. Presentation with an acute cauda equina syndrome and its successful surgical management has not been previously reported. CLINICAL PRESENTATION: A 57-year-old woman experienced back pain and bilateral sciatica ascribed to diabetic neuropathy for 2 years. Over a 24-hour period she developed bilateral lower extremity weakness, saddle anesthesia, and bowel and bladder incontinence. Lumbosacral magnetic resonance imaging demonstrated a large cystic dilatation of the ventriculus terminalis. INTERVENTION: She was taken for emergency surgical decompression and cyst drainage. Immediately after surgery, she experienced significant increase in lower extremity strength and has since regained continence. CONCLUSION: Cystic dilation of the ventriculus terminalis should be part of the differential diagnosis for a cauda equina syndrome; surgical decompression with simple cyst drainage can result in excellent clinical results.

Decompression, Surgical↗