Does Shamblin’s classification predict postoperative morbidity in carotid body tumors? A proposal to modify Shamblin’s classification

Abstract

The objective of this study was to analyze the possible correlation between Shamblin's classification and post-surgical morbidity in the treatment of carotid body tumors (CBTs). Seventy-two patients with carotid body tumors were seen over a 22-year period. Twenty-three patients were excluded as they did not comply with the criteria of the objectives. All patients were grouped according to Shamblin's classification. We propose a modification to this classification and make a comparison by analyzing the surgical time and bleeding, as well as the neurological and vascular damage. We resected 50 CBTs in 49 patients, ranging in age from 18 to 73 years. Three groups were formed: group I with 8 (16%) patients, group II with 17 (34%) and group III with 24 (49%). Post-surgical neurological damage was observed in one patient (12.5%) from group I, in six (35%) from group II and in nine patients (37.5%) from group III. Vascular sacrifice had to be performed in 21% of class II tumors and in 8.7% of class III. None of the class I tumors required vascular sacrifice. No statistically significant difference existed for vascular or neurological risk in relation to Shamblin's classification. However, when analyzed according to the classification proposed herein, there was a correlation between Shamblin's classification and vascular sacrifice (P =0.001). There was a statistically significant correlation between the original Shamblin and the modified Shamblin regarding surgical time and bleeding. Shamblin's classification predicts only vascular morbidity. Neurological morbidity is not reflected in it and only reflects the surgeon's experience with CBT resections. Surgical time and bleeding are directly related to the Shamblin as it reflects the size of tumors in relation to the blood vessels. Shamblin's classification must be modified to be more objective so that the international reports can accurately reflect the morbidity related to it.

Diagnosis and surgical treatment of carotid body tumors: 25 years’ experience in China

“…Most of these cranial nerve injuries are temporary. The incidence of cranial nerve deficit after CBT surgery is 49% in the literature, which is comparable with the present data 9 .…”

Important observations made managing carotid body tumors during a 25-year experience

“…Advances in imaging have led to attempts to assign this classification preoperatively; however, some authors have stated that CBTs can only be given a Shamblin classification at or after surgery. 20 A recent small study of nine CBTs suggested that MRI can accurately predict Shamblin group preoperatively, and the maximum degree of circumferential contact of the CBT with the ICA on axial images is the criterion to predict the Shamblin group. In that study, tumor size and Shamblin group did not have a uniformly predictable relationship.…”

Sclerosing Paragangliomas of the Carotid Body: A Series of a Rare Variant and Review of the Literature

“…12 This Shamblin class tumors that infiltrate the vessel walls at any site, regardless of size or need for reconstruction, with subsequent confirmation of infiltration clinically or histologically. 12 Postoperative complications are numerous and include transient ischemic events and stroke, cranial nerve dysfunction, hematoma causing respiratory obstruction necessitating surgical airway and death. 13 Of particular note is that of cranial nerve dysfunction, affecting approximately 30e40% of patients with Shamblin type 3 tumors.…”

“…14 In addition, early surgical resection avoids the increase in risk of postoperative neurological and vascular complications associated with increased tumor size. 12,18 Ongoing surveillance is required for patients with a familial disposition, bilateral tumors, or incomplete resections 19 because of the higher risk of malignancy or recurrence. …”