Ibn Jazlah and his 11th century accounts (Taqwim al-abdan fi tadbir al-insan) of disease of the brain and spinal cord. Historical vignette.

The 11th century was culturally and medicinally one of the most exciting periods in the history of Islam. Medicine of this day was influenced by the Greeks, Indians, Persians, Coptics, and Syriacs. One of the most prolific writers of this period was Ibn Jazlah, who resided in Baghdad in the district of Karkh. Ibn Jazlah made many important observations regarding diseases of the brain and spinal cord. These contributions and a review of the life and times of this early Muslim physician are presented.

The middle perforated substance of the diencephalon.

The diencephalon, upper brain stem and other basal brain structures are supplied chiefly by penetrating branches of the cerebral arteries. We examined the retrochiasmatic space between the superior border of the pons and posterior edge of the optic chiasm in six randomly selected adult fresh brain specimens. Lateral or anterolateral to the mamillary bodies, two small quadrangular spaces (2.5 x 3.5 mm) were found that were limited laterally by the junction of the optic tract and crus cerebri. These spaces were pierced on each side by 1 to 5 small penetrating branches (premamillary arterial complex) of the posterior communicating artery. A single, large and obliquely oriented penetrating branch of the posterior communicating artery (the so-called premamillary, thalamotuberal or mamillothalamic artery) was found to pierce this area in all specimens. Based on our findings, the above-mentioned vessels of this perforating substance supply the floor of third ventricle, hypothalamus and ventral thalamic nuclei. Hence, special attentions should be made during surgery in this area such as third ventriculostomy for hydrocephalus.

Neuroprotective effects of high-dose vs low-dose melatonin after blunt sciatic nerve injury.

INTRODUCTION: Melatonin, the secretory product of the pineal gland, has potent antioxidant properties. The aim of this study was to compare the effects of low-dose (10 mg/kg) vs high-dose (50 mg/kg) melatonin on early lipid peroxidation levels and ultrastructural changes in experimental blunt sciatic nerve injury (SNI). We believe this to be the first study to assess the dose-dependent neuroprotective effects of melatonin after a blunt peripheral nerve injury. MATERIALS AND METHODS: Rats were randomly allocated into 5 groups of 10 animals each. The SNI only rats underwent a nerve injury procedure. The SNI plus vehicle group received SNI and intraperitoneal injection of vehicle (diluted ethanol) as a placebo. The SNI plus low-dose or high-dose melatonin groups received intraperitoneal melatonin at doses of 10 mg/kg or 50 mg/kg, respectively. Controls had no operation, melatonin or vehicle injection. SNI was induced by clamping the sciatic nerve at the upper border of the quadratus femoris for 2 min. RESULTS: Sciatic nerve samples were harvested 6 h after nerve injury and processed for biochemical and ultrastructural analysis. Trauma increased the lipid peroxidation of the sciatic nerve by 3.6-fold (153.85 +/- 18.73 in SNI only vs 41.73 +/- 2.23 in control rats, P < 0.01). Low (P = 0.02) and high (P < 0.01) doses of melatonin attenuated the nerve lipid peroxidation by 25% and 57.25%, respectively (65.76 +/- 2.47 in high-dose vs 115.08 +/- 7.03 in low-dose melatonin groups). DISCUSSION: Although low-dose melatonin reduced trauma-induced myelin breakdown and axonal changes in the sciatic nerve, high-dose melatonin almost entirely neutralized any ultrastructural changes. CONCLUSION: Our results suggest that melatonin, especially at a dose of 50 mg/kg, has a potent neuroprotective effect and can preserve peripheral neural fibers from lipid peroxidative damage after blunt trauma. With further investigations, we hope that these data may prove useful to clinicians who treat patients with nerve injuries.

Approach to the cervical portion of the vagus nerve via the posterior cervical triangle: a cadaveric feasibility study with potential use in vagus nerve stimulation procedures.

OBJECT: The authors describe a technique in which the cervical portion of the vagus nerve is exposed during procedures such as neuroma resection or, more commonly, during the placement of a vagus nerve stimulator. METHODS: To test their hypothesis that a posterolateral approach to the vagus nerve may be feasible and efficacious, the authors performed dissection of the left-sided vagus nerve in 13 adult cadavers. The carotid sheath was exposed via the posterior cervical triangle, and the vagus nerve was identified posterolaterally. Measurements were made of the length of available nerve, and the anatomical approach was documented. As part of a comparison study regarding the available length of nerve, the authors exposed the left vagus nerve in five additional adult cadavers via a standard anterior approach to the carotid sheath, and compared the results obtained with each technique. A mean length of 12 cm of the vagus nerve was isolated when using the posterior approach to the carotid sheath, whereas a mean length of 11 cm of the nerve was documented when using the anterior approach. With the aforementioned posterior approach, no obvious injury occurred to the vagus nerve or other local neurovascular structures such as the spinal accessory nerve. CONCLUSIONS: Evaluation of the findings obtained in the present cadaveric study showed that a posterior approach to the vagus nerve is feasible. The technique for posterior exposure of the carotid sheath may prove useful in surgical exposures of the vagus nerve when a standard anterior method is not possible.

Vagus nerve stimulation for induced spinal cord seizures: insights into seizure cessation.

OBJECT: Vagus nerve stimulation is known to decrease the frequency, duration, and intensity of some types of intracranial seizures in both humans and animals. Although many theories abound concerning the mechanism for this action, the true cause remains speculative. To potentially elucidate a pathway in which vagus nerve stimulation aborts seizure activity, seizures were initiated not in the cerebral cortex but in the spinal cord and then vagus nerve stimulation was performed. METHODS: Ten pigs were anesthetized and placed in the lateral position, and a small laminectomy was performed in the lumbar region. Topical penicillin, a known epileptogenic drug to the cerebral cortex and spinal cord, was applied to the dorsal surface of the exposed cord. With the exception of two animals that were used as controls, once seizure activity was discernible via motor convulsion or increased electrical activity the left vagus nerve, which had been previously isolated in the neck, was stimulated. Following multiple stimulations of the vagus nerve and with seizure activity confirmed, the cord was transected in the midthoracic region and vagus nerve stimulation was performed. Vagus nerve stimulation resulted in cessation of spinal cord seizure activity in all (87.5%) but one experimented animal. Transection of the spinal cord superior to the site of seizure induction resulted in the ineffectiveness of vagus nerve stimulation to cause cessation of seizure activity in all study animals. CONCLUSIONS: The effects of vagus nerve stimulation on induced spinal cord seizures involve descending spinal pathways. The authors believe that this experiment is the first to demonstrate that spinal cord neuronal hyperactivity can be suppressed by stimulation of a cranial nerve. These data may aid in the development of alternative mechanisms for electrical stimulation in patients with medically intractable seizures. Further studies are now necessary to isolate which specific tracts, nuclei, and neurotransmitters are involved in this process.

Alternative uses for the subgaleal shunt in pediatric neurosurgery.

The subgaleal shunt has been used for the temporary bypass of the normal cerebrospinal fluid (CSF) pathways. We retrospectively reviewed all subgaleal shunts placed at the Children's Hospital, Birmingham, Ala., USA, from 1997 to the present and examined all uses (e.g. indication, length of follow-up) of the subgaleal shunt outside its use for temporary CSF diversion in premature infants with intraventricular hemorrhage and subsequent hydrocephalus. The average length of survival of the primary subgaleal shunt in this population was 32.2 days. We have had good success with subgaleal shunts in children with malignant brain tumors, intraventricular abscesses, chronic truncal wounds, chronic subdural hygromas and meningitis. However, the greatest utility has been in those scenarios in which the peritoneal cavities were not currently, but with time would be, candidates for distal shunt implantation. Examples of these instances are patients with hydrocephalus and necrotizing enterocolitis or hydrocephalus and preoperative abdominal wall pathology such as omphalocele.

Discernment of adipose versus nervous tissue: a novel adjunct solution in lipomyelomeningocele surgery.

OBJECTIVE: To determine a solution capable of discerning adipose versus nervous tissue, to aid in surgical separation of the adipose tissue which appears to be visually indistinguishable from nervous tissue in lipomyelomeningoceles (LMMs). METHODS: The following solutes (in normal saline) were investigated, both at 25 and 37 degrees C: beta-carotene, vitamin D, vitamin E, lecithin, hydrogen peroxide, lipase, protease, hyaluronidase, partially purified collagenase, purified collagenase, trypsin, trypsin plus purified collagenase and non-solute-containing saline (control). Each solution was applied to a pediatric lipoma to determine gross effects over a period of approximately 30 min. If a solution appeared to affect the adipose tissue grossly, studies of functional in vivo sensory evoked and spontaneous potentials using that particular solution were conducted upon sheep spinal cord, nerve roots, dura and peripheral nerve. Additionally, histological studies were conducted to determine the effect of that solution upon adipose tissue, spinal cord, myelin, dura and nerve roots. RESULTS: Of all solutions investigated, partially purified collagenase type 1 (T1C; Lot M0M4322, Code CLS-1, Worthington Biochemical Corporation, Lakewood, N.J., USA) at 37 degrees C was the most successful in grossly altering the consistency and appearance of adipose tissue. This change was more apparent over 20-30 min following application of the solution to the adipose tissue. Solutions not containing T1C did not show appreciable results; purified collagenase plus trypsin did not appear comparable or superior to T1C. No significant histological or functional change was noted when comparing the spinal cord, nerve rootlets, myelin, dura or peripheral nerve from the T1C-treated group versus normal (untreated) control groups. CONCLUSION: T1C appears to be a potentially effective solution for application during LMM surgery in the acute setting, and such use of an adjunct solution may significantly aid in the safe surgical resection of LMMs. Pending further research, this technique may be applied for other indications which require discernment or alteration of adipose versus nervous tissue.

Ninth cranial nerve stimulation for epilepsy control. Part 2: surgical feasibility in humans.

OBJECTIVE: To determine the anatomical and surgical feasibility of placement of a stimulator around the nerve of Hering (HN; a branch of cranial nerve nine). We previously determined the success of HN stimulation in controlling epileptiform activity in a canine model study. The present study assessed the ability to extrapolate the ease of surgical dissection and surrounding anatomy to humans. METHODS: Fifteen human cadavers (8 male, 7 female) were studied. The HN on each side was specifically evaluated in each specimen with respect to its presence, size, surgically accessible length below the mandibular angle, relationship to the internal carotid artery (ICA) and carotid bifurcation and relation to the common facial vein (CFV), thyroid cartilage (superior edge) and superior cervical ganglion (SCG). RESULTS: All 15 cadavers exhibited specimens of HN bilaterally, with the nerve diameter ranging from 0.5 to 1.5 mm (mean 1.0 mm); in relation to the ICA, the HN coursed anteromedially in 60%, anteriorly in 33% and anterolaterally in 7% of cases, and appeared to distinctly emerge at the level of the carotid bifurcation in all specimens. The surgically accessible length below the mandibular angle ranged from 6 to 30 mm (mean 15 mm). Relative to the carotid bifurcation, the superior edge of the thyroid cartilage was -35 to 33 mm (mean -5.4 mm) above; the CFV, which was clearly identifiable in only two thirds of the specimens, was -10 to 15 mm (mean 3.0 mm) above; and the inferiormost portion of the SCG was 6-30 mm (mean 16.6 mm) above. CONCLUSION: This study indicates that the HN was clearly present and surgically accessible in all human specimens. Based on the present study and our previous canine study, HN stimulation could be an important therapy for medically intractable epilepsy.