✓ The controversy over whether to use a posterior or anterior approach for surgical treatment of soft cervical discs is still largely unsettled. However, although the posterior approach may be underutilized, it has distinct advantages when there are specific indications. Out of a large pool of cases, 53 patients presented with acute monoradiculopathy caused by soft cervical disc herniation. In 36 of these, the disc was sequestered (nonconfined) and was posterolateral to the disc space as seen on computerized tomography-myelography. Distinct motor weakness was a common clinical finding in all 36 cases. These patients were treated by using a 2- to 3-cm skin incision for the posterolateral microsurgical approach. The extent of the lateral facetectomy depended upon the relationship between the nerve root and the disc. All fragments were lateral to the dural sac and were sequestered through the anulus fibrosus and the posterior longitudinal ligament. Sequestrations were removed under direct microscopic vision, but the disc space was not entered.
Pain relief and motor-power improvement in the affected radicular distribution were immediate in all patients. Sensory deficit and residual motor loss improved dramatically with normalization at approximately 6 months. No complications occurred and the mean hospital stay was 2 days. The follow-up period varied from 4 to 42 months with a mean of 26 months. Thus far, there have been no recurrences or other associated complications. By using strict selection criteria and a microsurgical posterolateral approach with removal of the sequestered disc fragment, excellent results with normalization of the monoradiculopathy can be obtained. The ease of this technique, low risk, minimal complications, and excellent results make it an attractive alternative to the anterior approach. The clinical presentations, specific indications, surgical technique, and clinical results are discussed; and a prototype of a small cervical self-retaining retractor is described.
E. Francois Aldrich, Peter B. Weber and Wayne N. Crow
✓ Fifty consecutive patients requiring posterior cervical fusion for various pathologies were treated with Halifax interlaminar clamps for internal spinal fixation. Fusion involved the C1–2 level in 17 cases, the C1–3 level in one, and the lower cervical area (C2–7) in 32. No patient was lost to follow-up review, which varied from 6 to 40 months (average 21 months). Fusion failed in five patients, three at the C1–2 level, one at the C1–3 level, and one at the C2–3 level. Screw loosening was the cause of failure in four patients, and in one the arch of C-1 fractured. No other complications occurred. Because of the lack of complications, avoidance of the hazards of sublaminar instrumentation, and an excellent fusion rate, this technique is highly recommended for posterior cervical fusion in the lower cervical spine. Atlantoaxial arthrodesis was achieved in only 14 (82%) of 17 patients, however, which might be due to the higher mobility at this multiaxial level. Improved results in this region may be possible by using a new modified interlaminar clamp, by performing adequate bone fusions, and by postoperative external halo immobilization in high-risk patients.
E. Francois Aldrich and C. Mauritz van den Heever
✓ For relief of meralgia paresthetica the authors have developed a suprainguinal ligament approach for decompression of the lateral femoral cutaneous nerve of the thigh. This proximal approach offers an alternative to the standard infraligament methods. Its chief advantage is that identification of the nerve trunk is easy and accurate. This avoids the tedious dissection involved in looking for small distal branches with their variable location. Lysis is easily performed, and angulation of the nerve in the iliac fossa is avoided. With this method, poor operative results can usually be eliminated.
E. Francois Aldrich, Wayne N. Crow, Peter B. Weber and Thomas N. Spagnolia
✓ Twenty-one patients requiring posterior cervical fusion were treated with magnetic resonance (MR) imaging-compatible Halifax interlaminar clamps for internal fixation. Various levels were involved: the C1–2 level in eight cases, the C4–5 level in four, the C5–6 level in three, the C6–7 level in three, the C4–6 level in two, and the C5–7 level in one. Bilateral clamps were used in 18 cases and unilateral clamps in three. Autogenous iliac bone grafting was performed in all cases but one. Follow-up periods ranged from 1 to 18 months (average 9.2 months), with no complications or mechanical failures occurring thus far. Follow-up diagnostic studies revealed rigid fixation and fusion in all cases. The MR imaging-compatibility of the clamps allowed excellent follow-up studies with minimal artifact. Because of their ease of use, rigid stabilization, good results, lack of complications, and compatibility with MR imaging, the Halifax interlaminar clamp with bone grafting provides an ideal method for posterior cervical stabilization.
J. Marc Simard, E. Francois Aldrich, David Schreibman, Robert F. James, Adam Polifka and Narlin Beaty
Aneurysmal subarachnoid hemorrhage (aSAH) predisposes to delayed neurological deficits, including stroke and cognitive and neuropsychological abnormalities. Heparin is a pleiotropic drug that antagonizes many of the pathophysiological mechanisms implicated in secondary brain injury after aSAH.
The authors performed a retrospective analysis in 86 consecutive patients with Fisher Grade 3 aSAH due to rupture of a supratentorial aneurysm who presented within 36 hours and were treated by surgical clipping within 48 hours of their ictus. Forty-three patients were managed postoperatively with a low-dose intravenous heparin infusion (Maryland low-dose intravenous heparin infusion protocol: 8 U/kg/hr progressing over 36 hours to 10 U/kg/hr) beginning 12 hours after surgery and continuing until Day 14 after the ictus. Forty-three control patients received conventional subcutaneous heparin twice daily as deep vein thrombosis prophylaxis.
Patients in the 2 groups were balanced in terms of baseline characteristics. In the heparin group, activated partial thromboplastin times were normal to mildly elevated; no clinically significant hemorrhages or instances of heparin-induced thrombocytopenia or deep vein thrombosis were encountered. In the control group, the incidence of clinical vasospasm requiring rescue therapy (induced hypertension, selective intraarterial verapamil, and angioplasty) was 20 (47%) of 43 patients, and 9 (21%) of 43 patients experienced a delayed infarct on CT scanning. In the heparin group, the incidence of clinical vasospasm requiring rescue therapy was 9% (4 of 43, p = 0.0002), and no patient suffered a delayed infarct (p = 0.003).
In patients with Fisher Grade 3 aSAH whose aneurysm is secured, postprocedure use of a low-dose intravenous heparin infusion may be safe and beneficial.
Michael T. Koltz, Adam J. Polifka, Andreas Saltos, Robert G. Slawson, Young Kwok, E. Francois Aldrich and J. Marc Simard
The object of this study was to assess outcomes in patients with arteriovenous malformations (AVMs) treated by Gamma Knife stereotactic radiosurgery (SRS); lesions were stratified by size, symptomatology, and Spetzler-Martin (S-M) grade.
The authors performed a retrospective analysis of 102 patients treated for an AVM with single-dose or staged-dose SRS between 1993 and 2004. Lesions were grouped by S-M grade, as hemorrhagic or nonhemorrhagic, and as small (< 3 cm) or large (≥ 3 cm). Outcomes included death, morbidity (new neurological deficit, new-onset seizure, or hemorrhage/rehemorrhage), nidus obliteration, and Karnofsky Performance Scale score.
The mean follow-up was 8.5 years (range 5–16 years). Overall nidus obliteration (achieved in 75% of patients) and morbidity (19%) correlated with lesion size and S-M grade. For S-M Grade I–III AVMs, nonhemorrhagic and hemorrhagic combined, treatment yielded obliteration rates of 100%, 89%, and 86%, respectively; high functional status (Karnofsky Performance Scale Score ≥ 80); and 1% mortality. For S-M Grade IV and V AVMs, outcomes were less favorable, with obliteration rates of 54% and 0%, respectively. The AVMs that were not obliterated had a mean reduction in nidus volume of 69% (range 35%–96%). On long-term follow-up, 10% of patients experienced hemorrhage/rehemorrhage (6% mortality rate), which correlated with lesion size and S-M grade; the mean interval to hemorrhage was 81 months.
For patients with S-M Grade I–III AVMs, SRS offers outcomes that are favorable and that, except for the timing of obliteration, appear to be comparable to surgical outcomes reported for the same S-M grades. Staged-dose SRS results in lesion obliteration in half of patients with S-M Grade IV lesions.