Nevan G. Baldwin

Anatomy of the Thoracic Pedicle

Thoracic pedicle anatomy (interpedicular distance, transverse and sagittal pedicle widths, transverse and sagittal pedicle angles, and the distance from the axis of the pedicle to the axis of the transverse process) was assessed in 11 cadavers of elderly people. The cadaveric spines were extensively dissected to augment the accuracy of the measurements via caliper and goniometer. The results were compared with those of previous studies that assessed pedicle anatomy with computed tomography, direct measurement, and three-dimensional morphometry. Between the studies, significant differences were found in transverse pedicle width and transverse and sagittal pedicle angles. These morphometric differences may reflect either the diversity of the techniques used to measure the pedicle anatomy or sampling variation. This article presents a previously unreported morphometric finding, the rostral-caudal distance from the thoracic pedicle to the midpoint of the base of the transverse process. At T1, the transverse process is 5.45 +/- 1.2 mm rostral to the pedicle. This relationship gradually changes as the thoracic spine is descended, so that at T12, the transverse process is 6.6 +/- 2.4 mm caudal to the pedicle. Crossover consistently occurs at the T6-T7 region. Although the transverse process is a reliable external landmark for the location of the pedicle in the lumbar spine, this relationship in the thoracic spine is variable and only moderately predictable.

Hypertrophic neuropathy of the cauda equina: case report.

OBJECTIVE AND IMPORTANCEHypertrophic neuropathy of the cauda equina (HNCE) is a rare form of peripheral neuropathy. The diagnosis is complicated by an insidious clinical presentation and complex radiographic images. We present a case of HNCE caused by chronic inflammatory demyelinating polyneuropathy with symptomatic improvement after decompressive lumbar laminectomy and dural expansion. CLINICAL PRESENTATIONA 54-year-old woman with a history of back pain since she was in her 20s presented with low back and radicular pain that had increased during a period of 6 months, bilateral lower-extremity weakness, and sensory loss in the right thigh. Magnetic resonance imaging of the lumbosacral spine revealed multiple, poorly enhancing mass lesions and apparent intrathecal nerve root thickening from L1 to L5. INTERVENTIONAn L1-L5 decompressive laminectomy, performed with continuous somatosensory evoked potential and electromyographic monitoring, revealed multiple segmentally enlarged nerve roots. One nerve root that did not respond to high levels of stimulation was identified. This root was resected and submitted for pathological analysis. The dura was expanded with an 11-cm-long dural patch. The pathological examination revealed hypertrophic neuropathy, with extensive S-100-positive “onion bulb” formation. The patient’s symptoms improved postoperatively. CONCLUSIONHNCE is a rare disorder that can cause radicular pain and lower-extremity weakness, sensory loss, and hyporeflexia. One possible cause is demyelinating polyneuropathy. Although medical management is typically effective in the treatment of demyelinating polyneuropathy, it has little effect on compressive symptoms caused by intradural nerve root enlargement. As this case demonstrates, surgical management of symptomatic radiculopathy by lumbar laminectomy is a reasonable and effective approach to the treatment of HNCE.

Resection of giant invasive pituitary tumors through a transfacial approach : technical case report

Giant invasive pituitary adenomas are rare tumors that have been reported to extensively involve the cranial base, as well as other intra- and extra-cranial structures, making surgical resection by traditional approaches impossible. We report two cases, each of a giant invasive adenoma involving the entire length of the clivus and adjacent structures that was resected via a transfacial approach with excellent results. Both tumors were in middle-aged men; one was nonsecreting, and the other secreted follicle-stimulating hormone alpha-subunit. Most previously reported giant invasive adenomas have been prolactinomas. Both tumors were resected via a transfacial approach that incorporated an osteoplastic maxillotomy with palatal division and a posterior pharyngeal incision that provided exposure from the suprasellar region to C2. Both of the patients received postoperative radiation and have done very well. Their cosmetic results were excellent. The complications included postoperative meningitis in one patient and a nasal voice in the other. The transfacial approach provides excellent access for this type of extensive midline tumor requiring resection from the suprasellar region down to the foramen magnum.

Resection of Giant Invasive Pituitary Tumors through a Transfacial Approach

GIANT INVASIVE PITUITARY adenomas are rare tumors that have been reported to extensively involve the cranial base, as well as other intra- and extra-cranial structures, making surgical resection by traditional approaches impossible. We report two cases, each of a giant invasive adenoma involving the entire length of the clivus and adjacent structures that was resected via a transfacial approach with excellent results. Both tumors were in middle-aged men ; one was nonsecreting, and the other secreted follicle-stimulating hormone α-subunit. Most previously reported giant invasive adenomas have been prolactinomas. Both tumors were resected via a transfacial approach that incorporated an osteoplastic maxillotomy with palatal division and a posterior pharyngeal incision that provided exposure from the suprasellar region to C2. Both of the patients received postoperative radiation and have done very well. Their cosmetic results were excellent. The complications included postoperative meningitis in one patient and a nasal voice in the other. The transfacial approach provides excellent access for this type of extensive midline tumor requiring resection from the suprasellar region down to the foramen magnum.